


Something Like A Star

by blacktail_chorus



Category: Sherlock (TV)
Genre: AU: Sherlock is a proper alien, Adventure, Alternate Universe - Science Fiction, Angst and Humor, BAMF!John, Bittersweet Ending, Case Fic, Friendship/Love, Gen, Platonic Love, from outer space
Language: English
Status: Completed
Published: 2014-09-24
Updated: 2015-11-28
Packaged: 2018-02-18 14:26:16
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 11
Words: 21,953
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2351630
Author URL: https://archiveofourown.org/users/blacktail_chorus/pseuds/blacktail_chorus
Summary: <blockquote class="userstuff">
              <p>
  <i>"You have questions."</i>
</p><p>  <i>"I do, yeah," John conceded.  "But as soon as I ask them you're going to tell me I'm focused on the wrong thing and missing the point entirely.  So why don't you just tell me?  Only," he paused. "How is it we're talking right now?  Communicating, beings from different worlds?"</i></p><p>---</p><p>In which John discovers that it really is all just transport. A chance encounter reveals Sherlock's true nature to his friend and sets the pair off on a race to uncover a murderer... or at least, that's what Sherlock tells John. But there is more going on than even Sherlock comprehends.</p>
            </blockquote>





	1. Chapter 1

**Author's Note:**

> All my love and gratitude to betas extraordinaire Nikoshinigami, for helping me reimagine what this story was meant to be, and BiancaAparo, for dragging it out of me inch by inch (by INCH) with tireless cajoling, patient reading, and motivational suggestion.
> 
> This universe has many elements drawn from my favo(u)rite sci-fi books and TV franchises. If you think you see an homage, you're probably right!

John strode along Baker Street, headed home after a long day at the surgery. His collar itched and his belt cut against the tops of his hips; he couldn't wait to get out of his starchy work clothes. He'd have to make a beeline upstairs, though, to avoid whatever Sherlock had begun cooking up that morning. He wondered what new sights and smells would greet him upon arrival, for he was relatively certain a new experiment was in the works. The increased activity signaled relief after nearly two weeks of enduring moods that were foul even by Sherlock's standards, and John was eager to enjoy some (relative) peace and quiet.

He spotted a tall, shapely brunette as she exited Speedy's and began walking in his direction. She wore an apron and carried two large rubbish bags in her hands, clearly headed for the bins in the alley nearby. The rattle of the bags as they jangled against one another punctuated each of her steps. John flashed a smile as she approached, which she returned briefly before passing him by.

In the next moment, he heard a large clatter behind him and the woman's voice sighing. "Damn." He turned to see that one of the bags had ripped, strewing cans, bottles, and boxes across the sidewalk. (The recycling, he thought to himself.)

"Would you like some help, miss?" John offered. The mess was just in front of the alley and the bins were nearby. 

"Oh, not at all," the woman protested. "It's fine, thank you, really."

"No, no, it's no trouble," John replied. "I only live just over there. Let me give you a hand." He turned on his most charming grin and smoothed out his jacket before bending down to gather cans in his arms.

"If you insist," the woman said, offering a shy smile in return. As they worked, John chatted away, flirting shamelessly and causing a blush to rise in the woman's cheeks. When the last bottle had been tossed in the bin, he turned to her and offered a handshake.

"I'm John, John Watson," he stated.

"Anna," she replied, taking his hand.

"How would you like it if I offered to buy you a drink after your shift ends, Anna?" John asked.

The blush deepened on Anna's face. A familiar snort broke through the moment, emanating from behind a bin several feet away. "I'm sure she would like that very much, John, but I imagine you'd rather not get involved with an unfaithful woman whose boyfriend has a vindictive streak a mile wide."

"Sher-lock..." John started, rolling his eyes.

"Maybe some other time, John Watson," Anna said, releasing John's hand and stepping away. "But, um, thanks for helping with the cans!" She glanced back at the alley before turning and walking back to the sidewalk at high speed.

John tromped back to the talking bin. The odor of rot, faint at the entrance, grew more intense as he made his way in. John hissed his breath in through his mouth to avoid the full brunt of the smell. "Thanks for that, mate," he said. "What on earth are you doing back here?"

Sherlock had his back to John and was lazily picking through a pile of overflowed rubbish. "Experiment," he offered. "I'll see you back at the flat."

A decomposition experiment, then. Delightful. His favorite. Well, he supposed the flat had smelled almost normal for an entire week, so he really should be grateful for that, if nothing else. As he turned to go, he noticed a shimmer in the patch of air next to his flatmate. He paused to look more closely.

"Look at--" he started, then gasped as the shimmer solidified into a form unlike any other John had ever seen. The overall shape was serpentine, but it was covered in luxurious, silky hairs. Each hair was flat and became wider towards the end. Several tentacle-like appendages with a similar shape to the hairs were engaged in a variety of activities, including one wrapped around Sherlock's wrist and another pressed to his temple. The creature's head reminded reminded John of the back end of a squid, with eyes gazing calmly from fleshy protrusions near the pointed nose. Overall, the creature could not have been less than two meters in length, and as thick around as a man's torso. Its glossy, glimmering appearance stood out against the bits of detritus and unidentified stains it had curled around to avoid.

"Oi!" he cried. Sherlock turned abruptly to look at him, then whipped his head towards the big blue... snake thing. Sherlock's reaction only increased John's level of shock and surprise.

"Oh, bollocks."

"What? What is that?"

The creature slowly turned its head and fixed John with its gaze.

"Ah... what's what?" Sherlock said with bluster.

"You know very well what--oh god," John groaned. "You bloody drugged me, didn't you. Again. And now I'm hallucinating. Aren't I?" He huffed out a dry laugh and threw up his hands. "You, what, covered the cans with something? Paid off the woman from the shop? Did you warn her about the hallucinations first? Christ!"

"I--"

"Nope. No. I'm going back to the flat, back there right now, Sherlock, and I'm going to have a cup of tea, and after that you get _exactly_ one chance to explain to me what the _hell_ you were thinking after I expressly forbade you from experimenting on me again. _And_ you're going to go apologize to that woman." He set his jaw and narrowed his eyes.

The creature hadn't moved. It certainly looked like a vision: totally silent, completely placid. John had patients who'd had hallucinations from medication side effects, and they frequently reported that the visions were eerily calm.

"The flat. Yes. Good. Ah, I'll be along in a minute then, shall I?" Sherlock asked tentatively.

"Bloody hell," John muttered. He turned on his heel and stomped off towards 221B Baker Street.

\----

The kettle had just boiled when the front door opened and Sherlock entered the flat. John looked up from his seat in the kitchen. "You're early," he said icily as he stood and began to make the tea.

"Hmmm," Sherlock replied absently. He walked over to grab his laptop and moved to his armchair, flipping the computer open and beginning to type furiously.

"You said you'd tell me what was going on," John reminded him, suddenly impatient. He savagely dunked the teabag into his cup before yanking it out and tossing it in the bin. Craving the acerbic tannins, he blew over the cup's rim furiously to speed its cooling down. His collar still itched; he hadn't had time to change.

Sherlock huffed and continued clattering on the keyboard.

"You drugged me, Sherlock," John prompted. "What the hell was that all about? What were you doing back in that alley?"

With a final fierce click, Sherlock finished his electronic tirade and closed the computer with a snap. "What?" he said, finally looking up at John. "Oh. Um. I can explain," he began.

John said nothing. He remained standing at the entrance to the sitting room.

"I didn't drug you, to start."

"Then who did?"

"As far as I know, you were not drugged at all," Sherlock continued.

John gripped his tea with both hands and willed the radiating warmth to help him calm down. If Sherlock was going to be cagey, persistent precision would be more effective than another explosion just now.

"I was hallucinating. I saw a big blue snake thing with its appendages wrapped around your body. Why is that, then?" John asked.

"Um." Sherlock looked away, seemingly distracted and a bit... distressed?

"If you're sitting there, working out how best to lie to me right now--" 

"You weren't hallucinating, John," Sherlock blurted out. He opened his mouth to say more, then shut it and compressed his lips into a firm line. 

"Well that sure as hell didn't look like a costume, and I don't think I'm in a play."

John could see his flatmate's distress more clearly now. Waiting, he blew over his tea once again. Eventually, Sherlock appeared to come to some decision.

"What you saw was an 'alien,' I believe you'd call it. Or perhaps you prefer 'extraterrestrial being'," Sherlock said, drawing out the final two syllables.

Squeezing his eyes shut in frustration, John reflexively slurped at his tea. His tongue and palate immediately erupted in pain and he opened his mouth to let the scalding liquid dribble back into the cup. "Christ!" he yelled.

"Do you need ice?" Sherlock offered, half-rising from his chair.

John waved him away and spun back into the kitchen to draw up a glass of cool water. He took a large sip and swirled it around in his mouth for a moment before swallowing. "You shouldn't put ice directly on a burn," he mumbled before taking another sip to calm his throbbing mouth.

"Oh," Sherlock said. He'd settled awkwardly back into his seat.

John remained in the kitchen, standing at the sink. He didn't look over. "Really. Proper aliens, from outer space. And I'm supposed to believe what, that you're helping to coordinate a secret alien invasion?" he asked.

"Hardly," Sherlock sniffed. "I suppose, if I think about it, we're really here to do the opposite."

"What do you mean, 'we'?"

"I mean that I am also a 'proper alien,' from outer space."

John really, really wished he could drink his tea. "Stop this, Sherlock," he began. His voice was low and deadly calm. "Stop playing with me. I'm really not in the mood."

"For God's sakes, John, just listen!" A desperate edge colored Sherlock's voice.

"Then stop all this nonsense and tell me what's going on. Spit it out!"

"All right!"

Apparently John's command had spurred something in Sherlock to action. He lunged into the kitchen and seized a pot from the cupboards, filling it with water and throwing it on the stove. He poured a liberal amount of salt in while reaching for a thermometer with his other hand. John was dumbfounded. He was cooking? Now? "What are you--"

"Be quiet. I'm going to show you." Sherlock resolutely kept his back to John while he stirred the pot and watched the temperature rise. When the brine met with his satisfaction he poured it into a large beaker and strode over to the sofa. Lying down on his side, he placed the beaker on the floor next to his head. His eyes glazed over and his body began to tremble.

The shuddering intensified and his jaw worked as though he might vomit. John instinctively stepped towards him but stopped short as a viscous red goo began to pour from Sherlock's nostrils into the beaker below. As the last of the goo dropped away, he went utterly limp on the couch.

John rushed forward. "Sherlock!" he cried, falling to his knees to assess his friend's body. Breathing was even and pulse was steady, but the eyes were fixed and unfocused when John pulled up the eyelids to check. John quickly unbuttoned the top of Sherlock's shirt and pressed his knuckles against his chest, rubbing vigorously back and forth. The pain of the sternal rub failed to elicit a response; his friend appeared to have dropped into a deep unconsciousness. A drug overdose? How?

John rocked back on his heels and reached for his phone, prepared to call 999 at once. A vivid red color caught his eye and he glanced down at the beaker by his side. The goo that had extruded from his friend's nostrils had coalesced into a blobby shape. It pulsed faintly and undulated within the beaker, looking like something very much alive.

Frozen to the spot, John jerked his vision back up to the body of his friend. He looked back and forth and a wave of nausea began to rise in his throat. Closing his eyes, he focused on inhaling and exhaling in calm, even breaths. 

After a moment, he allowed himself to open his eyes and considered the body of the man in front of him. Sherlock, John would have called it moments ago. But now he was able to see that the body more accurately _belonged_ to Sherlock... Sherlock, who was really the red pulpy shape floating in the water at his feet.

Right. His best friend was an alien, then. John's mind flashed back to the moments, both public and private, when he had stood up for Sherlock's humanity in the face of opposition. A small giggle escaped his lips. _A bit off the mark there, Watson, weren't you,_ he thought.

His simmering anger from moments ago had been swept aside by the laser focus that arose during a perceived medical emergency. Now that, too, was gone, and John felt a bit dazed. Empty. Aliens, then. Regular ones and... parasites? Good thing he was caught up on his Doctor Who.

The blob--Sherlock!--chose this moment to become agitated, quivering and rolling into more forceful undulations. The red color flicked through hues from cherry to crimson. John's giggle bubbled up once more. Here was Sherlock, then, without any limbs or voice at all, still managing to convey his immense irritation with the entire situation and impatience with the amount of time it was taking John to catch up.

Realizing what he had to do next, John picked up the beaker. He reached in and grasped Sherlock gently, then lifted him (it?) out of the water. It (he?) was warm and not at all slimy. Just smooth, and wet. John squeezed a bit experimentally and found the goo pushed back. John pressed it to Sherlock's body's face. The goo found the nostrils and began to work its way back inside. Sherlock's body trembled once more. When the goo had made a complete re-entry, Sherlock's eyes snapped open and he erupted into a massive sneezing fit.

John could not hold back his laughter. He sat back on the floor and rubbed at his face, wiping away tears. Sherlock sat up abruptly and turned his formidable gaze towards his flatmate, adopting a puzzled expression when confronted with John's state. "What do you find so _funny_?" He snapped the final word.

"Oh," John gasped. He looked up at him with a jagged grin. "I understand now. It really is all just transport!"


	2. Chapter 2

"You have questions."

They were now sitting across from one another in their respective armchairs. The beaker and pot had been cleared away and John was nibbling on a packet of nuts pulled from the cupboard. The now-cooled tea was forgotten in the kitchen.

John's manic mood had not lasted long. _Persistence,_ he reminded himself. _Calm. He can't explain if you wring his neck._

"I do, yeah," John conceded. "As soon as I ask them you're going to tell me I'm focused on the wrong thing and missing the point entirely. So why don't you just tell me? Only," he paused. "How is it we're talking right now? Communicating, beings from different worlds?"

Sherlock's sigh showed that John had proved himself right. "Well, _I'm_ speaking the Queen's English," he sniffed. "Though I don't know if I can say the same of you."

John remained silent, waiting. He crunched down on a nut, taking care to avoid hitting the tender burned spots on the top of his mouth.

"I am what you might call a symbiote," Sherlock continued. "Normally, my people join exclusively with one host race from our home world. That would be the 'blue snake' you saw in the alley just now. As I was born on this planet, however, I had to make other arrangements."

John paused his chewing while the implications of this idea caught up with him. "But then who..." He blanched. Whose mind had this... symbiote... overtaken? Who was sitting across from him in that chair?

"Oh, don't look at me like that," Sherlock snapped. "This body was a vegetable, a John Doe in the hospital with no hope of recovery. Surely you noticed the comatose state it entered when I removed myself. My people made the arrangements through the human scientific team we liaise with."

"Your people? So Mycroft..."

"Fully human. Not actually my brother. His parents were among the scientists, and they agreed to have me pose as their adopted son. This body was fourteen or fifteen at the time. I learned to speak and walk the way any human child might, though it didn't take me such a dreadfully long time."

John spared a thought for the young, unknown boy who had become Sherlock's host. What kind of life had he led to have ended up in such a state? This story was off to an inauspicious start, but he had to press on. He smiled thinly. "Right, then." He settled back in his chair and resumed picking at the nuts. "You'd better just start from the beginning."

Sherlock began, his affect flat. "My race is but one of many intelligent life forms in this galaxy. We are known generally as 'the Host.' Commerce and political alliances are practiced among the advanced civilizations, and in order to facilitate communication and travel in the face of vast interstellar distances, a system of Gates was constructed that allows nearly instantaneous transit from one point to another. Being invited to join the Gate community marks a significant level of achievement for a planet, signifying their ability to act on the galactic stage."

The nuts had been forgotten again. Last John had checked, Sherlock lacked even basic knowledge about Earth and its solar system, let alone the ideas behind _vast interstellar distances_. Had it been an act? Did he really know anything at all about the... entity... seated in front of him?

"My home world dispatches exploratory vessels to search for developing civilizations," Sherlock continued. "We study promising planets and install small-scale Gates so that they may be monitored in the long term, with information relayed to the powers that be. Once appropriate benchmarks have been reached, we make 'contact' on a large scale and begin the long process of incorporating them into the Gate community. You lot are quite a ways off from that phase, of course, but fortunately my people are very long-lived and very, very patient."

John scoffed. "'Patient' isn't exactly the word I'd use to describe you," he said. "Do you like to piss them off, too, then, your 'people'?"

A silent glare told John that hadn't been the most helpful thing to say. "Sorry," he muttered. "Keep going."

"Our vessel arrived on Earth approximately four decades ago after intercepting your early radio and television signals. You were determined to be suitable candidates for long-term monitoring and a small Gate in anticipation of your reaching maturity. That Gate is currently under construction, and monitoring is underway. We work with a small team of human scientists, primarily to obtain raw materials that we do not keep aboard the ship. This team is at present a highly classified secret within the British government, and has been overseen by Mycroft since our parents' retirement."

There was a pause as Sherlock's recitation came to an end. "Well, that's all completely mind-boggling," John said at length. "It's mad, really. Blue snake aliens with jelly brains here to shepherd us into the intergalactic community. Right. But how does all of that"--John waved his hands about--"explain you? In that body, in that armchair, sharing a flat with me?"

"They're not--it's not 'jelly brains.'" Sherlock rolled his eyes. "I said 'symbiote', not parasite. Host and symbiote are halves of a whole: each has its own self, its own mind, but together they are one being. For lack of better terms."

"Symbiote brains, then," John conceded. "Still. The flat? This body? You?"

"Like I said, I had to find alternate arrangements."

"Failed alien birth control?" John grimaced a bit at the images this conjured in his mind.

Sherlock gripped the arms of his chair. "Does it really _matter_?" he snarled. John sat up straighter at Sherlock's sudden change in demeanor. He very deliberately retrieved a nut from the packet on the table at his side.

"Apparently, yes," he replied, giving Sherlock a level look. He leaned back in his armchair, grateful for its stodgy support. "And you can hardly fault me for wondering. Snake aliens in dirty alleyways and my best friend is apparently its cousin."

"Yes, and what about your encounter in those rubbish bins." Sherlock's eyes narrowed, and their glint told John that Sherlock was off on another track entirely. "She was wearing her device and should have remained perfectly invisible to anyone who did not have a corresponding transponder." He pulled a small metal disc on a chain out from his pocket and held it up in front of his face, peering intently.

"You hid this from me," John interjected, trying to pull Sherlock back. "Why?"

"Surely you understand the nature of the term 'highly classified,' John," Sherlock said, his eyes still fixed on the dangling metal disc.

"Yes, but--"

"Mycroft wouldn't allow it." Sherlock muttered quickly, and grimaced. He twitched and locked his pale eyes on John's own.

"Oh," was all John could think to say.

"It is vital that he believes you are unaware," Sherlock continued. "And you're a terrible liar, always have been. Keep away from him, John. Clear?"

"Yes, but--"

"Right, then. Come on." Sherlock stood abruptly and pushed the metal disc back into his pocket. "I need you to help me test a theory." He practically leapt out the door and thundered down the stairs. John grabbed his jacket and followed close behind.

 _Persistance. Calm,_ John repeated in his mind. _I'll get to the bottom of this yet._

He scratched the itchy spot under his collar and hurried to keep up.

\----

That evening, Sherlock lay on his bed, shirtless and snarled around his sweat-drenched sheets. The burning flush that had raced over his body was subsiding. He wriggled and turned, trying to find a cool spot on the mattress, but his uncoordinated limbs only tangled him more. His breathing was beginning to slow and his eyes could finally focus: the storm was almost through. He'd survived another, and still John was none the wiser. In a few minutes he'd be able to get up to take a shower.

_Just had to be a show-off, didn't you?_

His mind whirred as he replayed the events of the day. Experimenting with the cloaking device had produced no answers; it appeared to work perfectly, in all manner of lighting conditions. The message he had sent to Mycroft detailing the device's malfunction (without any mention of John) had garnered a less-than-interested response. Minor glitch, more important things to worry about, your people aren't perturbed, no one was spotted, lay off it. Yet something about the incident made him hesitant to dismiss it entirely.

Really, though, if he hadn't deduced that woman with the rubbish bags and called John's attention to himself, he wouldn't be in this predicament now. He'd told himself he wanted to avoid the tedium of an inevitable altercation between the woman's boyfriend and John, but really it had been for fun: popping up unexpectedly with a crack observation, _being all mysterious with those cheekbones_...

Except now, Sherlock's plan had come apart. Well, his plan to not-plan, anyway. In his conversation with John, he'd neglected to mention perhaps the most important information of all: in two weeks, Sherlock Holmes would be leaving. For good. The Gate would be completed, and he, along with some select others, were being sent back to the home world, never to return. (And that tedious altercation never would have been his problem.)

Mycroft had outlined his cover story: he was to tell John that he'd been recruited on a mission for MI6 and would be out of communication for an unspecified amount of time. In a few months he'd be pronounced missing in action, presumed dead, and that would be the end of it. John would mourn but appreciate the sacrifice for Queen and country. Everyone would be satisfied. The whole thing was ridiculous, of course; even with Sherlock's acting abilities, John was sure to smell a rat. As if Sherlock would ever do such work, and for his brother, at that!

So Sherlock had decided he was simply going to disappear. Let Mycroft carry out his charade, when John came knocking. But now that John knew the truth about who Sherlock was, the story was even less likely to hold together in John's mind.

Why hadn't he just told John he'd been drugged, anyway? That had been his original intent. The truth about his associate had just sort of... slipped out. And then he'd "slipped out." And now?

Not that any of it should matter, really. Sherlock wasn't going to have to deal with John's reaction one way or another. He could still follow his original plan. He could just leave, with John none the wiser.

_...my best friend..._

Couldn't he?

Sherlock lifted an arm experimentally. He flexed each finger, feeling the precise pull of each tendon as the muscles in his forearm contracted. Control again, at last. He rolled out of bed and stumbled into the bath.


	3. Chapter 3

16:37: _greg pls tell me youve got something for him_

16:44: _mrs h may actually evict us if he keeps at it_

John risked a glance in Sherlock's direction. The consulting detective had slithered low in his armchair: his back was mostly pressed against the seat, and his legs jutted out into space, keeping him from sliding all the way down. Elbows against the armrests, he held a ratty hardcover reference book up to his nose. Normally, Sherlock-while-reading afforded the rest of 221 some peace and quiet, but for the past three quarters of an hour he'd chosen to accompany himself by stomping his feet with great gusto but no discernible rhythm.

Life after Sherlock's revelation had been... like this. So, quite normal. Sherlock hadn't offered any further information, so John hadn't asked. Direct questioning was undoubtedly the worst way of getting information out of him. He'd have to wait for an opportune moment and a carefully offhanded remark; that usually produced the best results.

Patience had never been one of John's strengths.

Sherlock's mobile buzzed. The man himself, however, did not react.

John cleared his throat, trying to break through the pounded cadences. "Aren't you going to get that?" he asked.

"No."

"No?"

"Why should I?" Mercifully, the stomping stopped. Sherlock lowered his book and met John's eye. "It's almost certainly Lestrade. You've sent two text messages in the past fifteen minutes, most likely to him, most likely asking if he's got anything on because you've grown tired of my studying. If he _had_ he'd certainly have contacted me without your prompting, meaning whatever he has to offer is no more than a four at best. Not worth my time."

"You call that studying?" John responded, incredulous.

"Clearly. This book--" here he waved the tattered volume around "--which is ostensibly about nineteenth century railroading, incorporates sections written in code that rely on the placement of certain stressed and unstressed words and syllables. I have to emphasize the stresses to work it all out."

"And you thought that pounding your feet was a superior method to perhaps tapping your fingers?"

"Why should that matter?"

"Just look at your phone!"

(If he didn't break out of the Sherlockian conversational logic cycle early on, John had learned, they often ended up in places he didn't care to be.)

With a long-suffering groan and a truly impressive eyeroll, Sherlock snatched up his phone and tapped at the screen. Suddenly, he pushed himself up in his chair and let the disturbed book fall to the floor.

"What a happy coincidence. Fresh one, just called in. Anderson hasn't had time to screw it up yet."

John hid his sigh of relief and stood to get his jacket.

\---

"Howard Miller, forty-three, research scientist. Wife found him when she came home from the shops this afternoon." Lestrade greeted them at the door to a neat white house in a neat suburban tract. "He's in the kitchen."

Sherlock brushed past without so much as a nod in greeting. John caught Greg's eye as he followed in his friend's wake, the thanks-and-no-problem conversation inferred and understood.

When John got inside Sherlock appeared to be examining everything but the body, so John decided he would start with what he knew best. The man was lying facedown on the floor, limbs askew, with a broken drinking glass not far from his right hand.

"His general appearance fits with the information Greg gave," John began. No response. "Looks fit, though I suppose he's got a bit of middle age around his waist there," he continued. The man was indeed generally trim. He was wearing athletic clothing but no shoes. His curly hair clung to his temples in dampened tendrils. Upon closer inspection, John realized his shirt was slightly sweat-stained. "He was perspiring. Might've just come back from a jog?"

John knelt down and began a cursory physical examination. The body was cool, but only just. The lively elasticity of the skin was jarring to the touch; the waxy sheen it carried looked as though it should be stiff and hard. John checked the man's pupils and looked for signs of trauma or illness of any kind. His hand brushed over something at the man's waist: he lifted up his shirt to reveal an insulin pump.

"Diabetic," John called out. "On insulin." He looked over at the broken glass on the floor and noted the clear, yellowy liquid puddled around it. "He was drinking juice just before he died. Could have had low blood sugar after exercise, and passed out before he could finish the juice to get his sugars back up. Hypoglycemic shock, possibly followed by head trauma, could have easily done him in."

He leaned over and dipped one gloved finger into the juice puddle, then brought it up to his nose to sniff. "Pineapple," he announced. "And... this is weird, it smells a bit like hot metal? Or... I can't quite place it."

This, finally, caught Sherlock's attention. He whirled around, abandoning his inspection of the kitchen's cabinets, and strode over to grab John's upraised hand. He took a whiff and a spark of recognition flashed through his eyes. He pushed John's hand away.

"Where is the victim's wife?" he called out to Lestrade, who had been watching the pair from the doorway.

The DI stepped into the room. "Can't she wait?" he asked. "She's in shock. I don't think she's up to your... well... y'know," he finished lamely.

"The wife," Sherlock repeated.

Lestrade (who had known the request would be futile at the outset) had already flipped through his notes to find her information and turned to lead the way. "Name of Henrietta Lacks," he informed them. "When she called this in she sounded pretty convinced her husband had been murdered. Seems a bit odd, since she'd have known about him being a diabetic," he said to no one in particular. Sherlock accordingly ignored him.

The trio headed over to where the wife was sitting two rooms away on a small, thin sofa. Her back was to them, and John could see that her spine was as rigid as her severely coiffed curly, black hair. An officer was sitting with her, making motions and noises of comfort.

"Excuse me," said Lestrade as they entered, "Henrietta, do you think you could answer just a few more questions?"

Henrietta turned around. "Oh," she said, with a note of surprise. She looked at each of the men in turn, but her gaze lingered on Sherlock. The curiosity and focus in her dark brown eyes was at odds with the tear-streaked puffiness of her face.

"Marm?" Lestrade prompted.

"Oh, yes, of course." She recovered her surprise smoothly. A tight smile passed over her lips.

"What is your connection with Bellatus Laboratories?" Sherlock plunged in.

This time the shock that crossed her face did not dissipate. "We--we both work there. We're research scientists. We each specialize in different branches of materials engineering," she offered.

"Then when you'd found your husband had been murdered, why on earth did you go and call the police?" he pressed on.

Now it was John and Greg's turn to be surprised. Henrietta offered only a sad little grin.

"I suppose I wasn't thinking clearly," was all she said in reply.

Sherlock scoffed and pulled out his phone, engrossing himself in composing a new message.

"Sorry," John interjected. "He's very... focused."

"It's quite all right," Henrietta said. "It's good to see he's doing well."

"Yeah...?" This conversation was getting more odd by the minute.

"Gather your officers, Inspector," Sherlock commanded as he put away his phone. "The British government will be here shortly. They will be taking this case from here. Come along, John," he finished, then turned to walk out of the room.

"Now, hang on!" Lestrade called out.

"They will explain it far better than I can," Sherlock dismissed him. "They won't be long. But I must be going. Now, John," he finished.

John caught Greg's eye and the two had another silent conversation. _What can you do?_ was all either had to say.

\---

As the two men left the house and walked towards the main road to hail a cab, John felt unbalanced by Sherlock's uncharacteristic silence. No deductions had been forthcoming; there was no post-case glee, or even snarls about the exercise having been a waste of time. Perhaps Sherlock was annoyed because the whole thing had, apparently, some sort of connection to Mycroft?

"So it was murder, then?" John ventured as they stood on the kerb, watching cars pass them by.

"Not your best line," Sherlock muttered.

"Seriously. What happened back there?"

"I'm not at liberty to say," Sherlock replied airily. "That's the phrase, isn't it? Top secret, and all that."

"Come on," John grinned, "You have government clearance? Or... wait, does this have something to do with your... er... your--"

"Yes," Sherlock interrupted. "And you know nothing. You weren't in the room when I questioned Dr. Lacks. I agreed with your assessment that Dr. Miller died from hypoglycemic shock. Alright?" With this, he turned and pinned John down with an earnest, piercing stare. "Do you understand?" he pressed further.

"Yes," John said warily.

"Good, because I'd rather your mind not be more scrambled than it already is."

" _What?_ " John took a step forward, then lowered his voice and asked intently: "Sherlock, are they doing something to Greg back there? Is the government--are they hurting them?"

"No, no," Sherlock waved his hand dismissively. "They'll be given injections, to induce a brief period of amnesia. It should only affect the past few hours at most. It's fortunate that I arrived quickly enough for that."

"You mean like _Men in Black_?" John asked, his mouth agape.

"What?"

"Never--Sherlock, don't be ridiculous, you can't muck around with people's _brains_ like that! Now, look, if Greg is--just look, you've got to tell me what's going on," John demanded.

"No, I don't," Sherlock raised his hand to forestall John's protest. "I'd rather show you instead."


	4. Chapter 4

"Here are the facts, John," Sherlock said upon arriving in Baker Street, just after leaving the crime scene. He'd whisked off his coat and strode to the center of the sitting room, pivoting to face John as he hung his own jacket by the door.

"Harold Miller was indeed an insulin-dependent diabetic. He was a model patient, superb at managing his disease. Obviously he exercised regularly, and his weight was well-controlled. He had charts and logs hung round the kitchen tracking his fitness and eating habits and blood sugar levels; clearly this control was maintained through meticulous attention bordering on the obsessive. This was not the sort of man who would experience severe, unexpected fluctuations in his blood sugar.

"He did go for a jog just before he died, and after he arrived home he poured himself his customary glass of pineapple juice to stave off his expected dip in sugar levels. Unfortunately for him, someone had added a compound to his drink that quickly proved fatal. He may have died before even hitting the ground.

"His wife arrived home shortly thereafter and found him, dead. Being of course intimately familiar with his habits, she knew at once that this couldn't have been related to his disease, and his age and fitness made something like a heart attack also unlikely."

"Why couldn't she have done it?" John broke in. "Seems like she'd have had the best opportunity." He had made his way over to his chair, settling down in preparation for the remainder of Sherlock's deductions.

Sherlock, still standing, snorted. "If she'd done it, do you think she'd have called attention to it? No, she would have called the police and reported him dead of hypoglycemic shock, as you'd initially assumed."

"Hang on," John interrupted again. "Why were you so surprised about her calling the police, when we spoke with her earlier?"

"Because they both worked for Bellatus Laboratories," Sherlock explained. "Pay stubs on the kitchen counter. That, plus the compound you smelled in Dr. Miller's drink."

"Is Bellatus Laboratories.... alien?" John ventured. A doubtful look crossed his face; he really had no idea what to call them.

"Not exactly. It is name of the cover organization for the group of scientists who liaise with them."

"I'm still not seeing why you don't think she should have called the police."

"Risk of exposure. The need for a cleanup operation. Bellatus requires its employees to report all unusual occurrences. Even if Dr. Lacks didn't smell her husband's drink, she should have followed protocol before getting outsiders involved."

"What was the compound that made that smell, exactly?"

Sherlock huffed in annoyance and raked one hand through his hair. "Irrelevant. As ever, you're wide of the mark, John."

"Yes, the point being you explaining to me why our government apparently has secret memory-altering injections that it uses to hide murders and perpetuate a massive cover-up," John returned. He didn't bat an eye.

"You have been watching far too many spy thrillers," Sherlock grumbled. He sighed.

John waited.

"Oh, Lestrade is fine!" Sherlock waved his hands dismissively. "The entire point of this operation is to prepare and welcome the human race onto the galactic stage. They don't want to damage you."

"Then why were you so adamant that I not get that injection?" John challenged.

"Because you wouldn't remember anything and then you wouldn't be able to help me with my plan," Sherlock answered, clearly holding back a final, "obviously."

"Plan for what? I thought you said the government was taking care of the case...?"

"Hardly. My people will not be concerned with a conflict that most likely involved only two humans, and the human investigators who will care are certain to be inept. It's down to us, John," he finished.

"'It's down to us?' As though that's ever been your reason for taking a case," John snarked. "What's got you so interested in this?"

Sherlock bit his lip and pivoted where he stood. "I--I can't explain now," he said, at length. "But I told you: I plan to show you. Now, will you help, or not?"

"Fine, alright," John conceded.

"Good. Now, first of all, you're going to have to let me go inside your head."

\---

Taking a deep breath, John shot one last glance at Sherlock's prone, unresponsive body before lowering his head towards the basin in front of him. He squeezed his eyes shut just before breaking the water's surface.

_This is it. I've actually gone completely mental. This is just insane._

Then, suddenly, a feeling came on like he'd snorted water up his nose. He fought the urge to sneeze. The sudden shock morphed into a dull pressure across his cheekbones and over his eyes; his sinuses were uncomfortably full.

_Full of an alien life form,_ his brain reminded him.

John braced himself for the next part, wherein Sherlock would apparently be secreting some substance to dissolve a small hole in the bone separating his sinuses from his brain case. _This_ part had come the closest to turning him off the idea altogether; there was a reason that no natural passageway existed to connect the outside world to the inside part of a human skull. To Sherlock, however, this concern had been utterly trivial. It was something all hosts had to undergo, after all, and his own human body had suffered no ill effects over twenty-odd years.

No, the thing that had concerned Sherlock the most, and John nearly as much, was the possibility of the other seeing into his own private mind.

In theory, a symbiote and a host only communicated through active participation on both parties' parts. At least, that is what Sherlock believed; he still knew nothing about his human host--not even the boy's name--and had assumed that was because the human was not consciously able to tell him. The host's thoughts and memories were not a filing cabinet to be rifled through. They could only be activated with intent. Or so he'd told John-- _Think about naming the cranial nerves for all I care, it will only be for a few minutes!_ \--and so he had hoped.

For Sherlock's plan to work, John had to be able to use the invisibility device, after all. As that technology was keyed to traces and markers of symbiote physiology, the only way John would be able to use the device was if those traces were inside of him. Hence, Sherlock would make a quick trip into John's head with the hopes that John's immune and circulatory systems would do their deeds. Simple, really. Very logical.

The pressure in John's sinuses diminished. Beyond that, though, he felt nothing. He sat back from the basin and took a deep breath. Oddly enough, he didn't even feel anything like a headache. _Right then_ , he thought, _it's on. So there's the olfactory nerves, the optic, oculomotor, trochlear...._ He began sifting through his anatomy mnemonics as he patted his face dry with a flannel.

All the while, Sherlock was stretching, making his blobby, gelatinous form transform into a thin membrane covering bumps and crevasses across the surface of John's brain. The storm of electrical signals charging through John's cerebral cortex soon resolved themselves into thoughts--English words--Sherlock could understand: <...the trigeminal nerves, the abducens, the facial nerves, the vestibulocochlear...> He also became vaguely aware of an image, perhaps a diagram? Yes, a diagram from a medical textbook, with each nerve lighting up as John thought its name in turn.

Belatedly, Sherlock realized he hadn't formulated a plan for what exactly _he_ should be doing during this little experiment. Surface thoughts, surficial ideas, those would be the key: he decided to start by sending John a "hello."

It was not, however, an English-language "hello." The greeting was his own people's language: a melding of feeling and abstract image, not anything having to do with phonemes or words or syntax. This hello was a smooth grey-blue, with a tinge of pink concern fringing the edges.

John's inner monologue immediately jumped its tracks. A stream of half-formed What and Oh my god spurted through his mind followed by a very deliberate <Sherlock?> and muffled droplets of Can he hear me of course what can he hear now--?

<Hello, John,> Sherlock tried again, using English words this time. <Don't stop your anatomy revisions on my account.> He was much more adept at controlling the breakthrough of background thoughts than John; it seemed that communicating with a conscious host brain was not so different from communicating with other members of his kind.

<Okay. Sure. Um. I think I was at the glossopharyngeal...?> And he was off again, clearly concentrating very hard in order to prevent his mind from jumping to other trains of thought.

But for all Sherlock's insults to the contrary, John's mind was not a straightforward thing. It was a rare moment when he was not thinking about at least two things at once; separate threads spooled along together, each alternately brought up to the fore.

Sherlock saw the second thread dimly. At first he mistook it for some background process, like the autonomous impulse for John's body to breathe. But over time it became stronger and more and more clear. It was a memory, running like a video on a loop.

And it was a memory that involved him: a memory of their conversation not ten minutes prior. Sherlock had been trying to convince John of his plan, but John was being irritatingly obstinate. He felt/saw John, frustrated and worried but simmering with excitement, reaching out and grabbing him by the shoulder. He saw John's memory of his own face curled in confusion and annoyance. Then, firmly: "I trust you, Sherlock. You know I do."

The conversation had gone on from there. (John had followed that statement with a sentence starting with "but...") The memory, however, centered around that one declaration, playing over and over again. And it was more than a video: the emotional foundation of that statement stood firmly beneath each word. _I trust you, Sherlock. You know I do._

Without thinking, Sherlock blurted a response in his own language. Jewel-green-blue, foamy fractals and sparkling tangerine starbursts framed his own visual memory of John, when he was trying to be stern but ruining the effect entirely with a twitchy smirk overtaking the corners of his mouth. Sherlock had no translation for this; his English vocabulary would not convey it.

Once again, John's thoughts in the present stuttered to a halt. A sing-songy voice had stuck on the name of the last nerve John's litany had come upon, creating a repeating background echo. <Sherlock?> John asked, tentative but deliberate.

<Time's up,> Sherlock decided suddenly. He moved to bend John's body back towards the basin but was met with immediate resistance.

<And we'll have _none_ of that, > John declared. He ducked his own head down into the basin, and Sherlock left the same way he'd come.

\---

Sherlock had been restored to his own host body. By mutual unspoken agreement, both retreated: John to the kitchen and Sherlock to his laptop at the desk.

At least the kitchen was (relatively) clean. Sherlock didn't think he was quite ready for a row over the refrigerator after... all that. He flicked through his inbox without truly reading any of it. If _that's_ what it was like for everyone else, always--constantly connected to another consciousness--he had to say he did not see the appeal. And if he couldn't stand to be in John's head, how awful would a stranger be? Perhaps there was a way to--

"Oh I'm a fool!" Sherlock growled, as the seed of an idea burst unexpectedly from another corner of his mind.

John popped back into the sitting room. "Well, that's hardly news," he quipped, sliding eagerly into familiar conversational territory.

Sherlock, apparently, had the same idea. He raked one hand through his hair and swiveled to face John, his focused, connecting-the-clues look firmly in place.

"The police, you kept asking, why not the police? That's just it: the perpetrator would have counted on Lacks recognizing the compound and following protocol, _not_ contacting the police. Otherwise, why choose such a recognizable and easily-traceable murder weapon? Obviously the perpetrator is convinced he can evade an internal investigation. What's more, it wasn't just a murder: it was a message."

"You mean like a warning to someone else, to back off?" John ventured.

"Precisely," Sherlock replied, a small smile rippling across his mouth. "But Dr. Lacks was clever. Her thinking wasn't muddled at all: she broke protocol on purpose. She used her grief and shock as a cover for the breach. She went after the slim chance that outside involvement would stir the pot, upset the killer's plans. And well she did," he concluded smugly.

"Does this alter our plan, then?" John's tone was carefully neutral.

"On the contrary. We should begin at once."

The game was afoot, and Sherlock was poised to commence the hunt. John nodded once.

"Alright. I'll go get the suitcase."


	5. Chapter 5

Like all good plans, this one began with a bit of breaking and entering. Only rather than entering a house, John and Sherlock needed to enter a spaceship.

Sherlock, wisely, had avoided any jokes about John's short stature when explaining what they would have to do. Otherwise, John would never have agreed to fold himself into Sherlock's largest suitcase. John prepared himself for travel: he packed some clothes around himself for padding and nestled a small rucksack with some essentials in his lap. Finally, he lay down to allow Sherlock to make the finishing touches.

"Lucky for you I'm not claustrophobic," John grumbled as Sherlock placed more padding over him. The suitcase was soft-sided and had some strategic rips to allow for better air transfer; the padding would disguise the outline of an arm or a leg and prevent injuries from unexpected collisions.

"Here," Sherlock said, slipping a chain over John's head. It contained a metal transponder disc like the one he'd shown John earlier. "I'm going to activate it now, to be sure it works. It will also be helpful if anyone decides they need to look inside."

Ordinarily, the transponder concealed the wearer from any creature who did not have another transponder. Some years earlier, though, Sherlock had fiddled with _this_ transponder to do the opposite: it rendered the wearer specifically invisible to others with transponders. (This modification had proved very useful in the past.)

Sherlock wore another, unmodified transponder of his own. The technology was keyed to work only with beings that contained symbiote biomarkers. This was why he'd needed to go inside John's head: he hoped the remnants he'd left behind would be enough for the transponder to work with. The transponder had variable size and sensitivity settings to account for different host sizes and any objects that needed to be carried.

He adjusted the settings until John blinked out of view. The field was too wide; he'd taken part of the suitcase with him. Sherlock still had hold of the disc and adjusted the settings further until the invisibility was contained inside. Then he let the disc go.

"Ow!" John's voice came from the empty space beneath the top layer of shirts below him. "That hit my face, you berk."

"Well I can't exactly see you," Sherlock retorted.

"Oh, let's just get on with it," John sighed.

Sherlock unceremoniously zipped the case closed.

\---

Being in transit wasn't nearly as uncomfortable as John had feared. He'd been worried about getting down the stairs and out of the flat, and the prospect of being wheeled over uneven pavement had not been appealing. The movement was actually quite smooth, and John had a bit of a floating sensation. He wondered whether Sherlock had some sort of hover device attached to the case, then smothered a chuckle. The transponder didn't do anything about sound.

In the dark and the quiet, his thoughts slid easily into rumination. He'd had Sherlock inside his head, barely an hour ago. After nearly four decades of being the only person inside his own mind, having company had been so bizarre he truly had no idea what to make of it. He didn't know where to begin. John mentally went through the setups and punchlines of a few crude jokes and reveled in the privacy he'd never realized his own thoughts could afford.

Sherlock was an _alien_. The color/shape/feeling sensations that had flooded his mind's eye had come from Sherlock: that was his real, true language. Sherlock hadn't just had to learn to walk and talk in his human body. He'd had to learn an entirely foreign idea of what communication meant.

John wondered whether he'd also been tutored in the appropriate arrangement of corresponding facial expressions and body language. That would certainly explain how keen and calculating he was when he observed anyone else's; he must have studied each minute detail with great care in order to become such a flawless mimic. John pictured a young teen seated in front of a mirror, practicing tilting his head and narrowing his eyes... or perhaps delicately raising one eyebrow under the guidance of a fresh-faced Mycroft Holmes.

Time rolled on. After over an hour of this, John's mind quieted and his chief complaints were really just the dark and boredom. To stave off muscle stiffness and cramping, John tried to relax his body and doze. He wouldn't fall asleep entirely--an ill-timed snore could be problematic, after all--but after years of medicine and the army it was not too difficult to settle into a half-state, not fully awake but ready to rouse himself quickly if necessary.

He felt warm. Warm and... suspended. Not as though the case were hovering, but rather as though his whole body, boneless, was submerged in a thick liquid. It was comfortable. Safe. He thought he could smell something a bit like hot metal.

Suddenly a frightened face flashed in front of his mind's eye. He started; it was gone before he could register much. Young, female, brown hair.

He felt a short, gentle kick land on the suitcase at about the location of his ribcage. He must have made the case move when he'd shocked awake; the kick was likely an admonition from Sherlock. _Be careful_.

John couldn't respond, of course. He settled in to try to doze again. Must've been a hypnic jerk. Those were unusual for him, and it probably wouldn't happen again.

The suspended sensation returned readily. John tried to keep his mind above the water, wary this time. And then the face came back.

It wasn't just a face. It was someone looking in a mirror--he _was_ the woman, looking at her own reflection in a bathroom. Her eyes were wide and her breathing was fast and shallow. Though her skin was dark John could tell she was drawn and unusually pale.

And she was screaming. She was screaming _inside_ her own mind, in a language John did not understand. Another voice was layered in with hers, and it was a voice John... recognized. Not an English voice, but rather a starburst of sensation and flickering colors`that very clearly communicated panic, panic, PANIC.

John gasped and struggled to break out. His eyes snapped open and he saw only darkness. He sucked in a deep breath and rubbed at his chest where his hands were curled.

" _John_ ," Sherlock's voice hissed from outside. "Be still, we're approaching a critical juncture!"

John was still, and taut as a wire. His wide round eyes searched the darkness as he worked to calm his breathing. He did not respond.

That voice, the second voice, the one in his head with the frightened girl. That voice had been Sherlock. He was sure of it.

What the hell was going on?

\---

The train carrying Mr. S. Holmes and his comically overlarge suitcase to Bristol was nearing its final destination. It was to be met by a car that would convey him to a location where he could get on the transport that would take him to the ship. That is, if John could manage to be _still_ for just a little while longer. Sherlock pressed his palm against the side of the case, letting John know they were about to get on the move.

Sherlock had told Mycroft that he had some items he wanted to take with him on the journey... home. Mycroft had offered, weeks ago, and Sherlock had brushed him off. As if there were any _thing_ from Earth that would be of use to him on another world. Now, however, he could use the offer to his advantage, smuggling John aboard under the guise of sentimentality for clothing and possessions.

Although if he could take with him what he truly wanted... hm. Oh yes, the violin. Of course. (Not that he'd be able to play, once he had a "proper" host. Perhaps not, then.)

Once in the car, Sherlock was thankful for the driver's silence. He supposed the man thought Sherlock was like the rest of his kind: quiet, deliberate, and enigmatic. Humans commonly had a difficult time with his people's notion of a conversation, even one adapted to human conventions. They soon learned that it was best to not initiate.

They soon arrived at a secluded location on the shores of the Bristol Channel, where the final transport was hidden. Sherlock and his luggage would not be the only passengers; Aunt was there, as were a few others who he hadn't bothered to remember. The latter studiously avoided his arrival.

Sherlock walked up to Aunt and extended his hand in greeting. She extended her own appendages in turn, wrapping one around his wrist and placing another against his temple.

<Hello.> She greeted him warmly in their language of shape and sensation. If he concentrated, he could resolve her signature bright green voice into its two components--host-yellow, symbiote-blue--but the unified whole was _Aunt_ entire.

<Sorry about the... interruption, last time I saw you,> Sherlock returned. Aunt was one of the few who had taken to Sherlock's relatively fast, direct (human) style of conversation. One of the few who had taken to Sherlock at all.

<Signal broadcast malfunction, I heard. Hardly your fault.> Aunt said. <Was your flatmate quite all right? Did he get angry with you for thinking you'd drugged him again?>

<He got over it soon enough.>

<Is this it, then?> she asked. <Have you come to stay on board until you leave? Looks like you've brought quite a lot with you.>

<No, it will be a few days yet. It was just easier to get all this out of the flat today, while John was out. And I have to satisfy some final physical tests. I'll be returning to London after.>

<You look well,> she offered. <I believe. At least, your skin looks its proper color.>

Sherlock smiled. Aunt's job was materials procurement; she hadn't needed to learn about human physiology in any great detail, and still fell back on her native understanding of sickness and health.

<Soon you won't have to worry,> Aunt continued. <They'll find a way to make you Whole. They'll heal you.>

It was an old platitude, a mantra she'd recited many times in the past. Sherlock suppressed his conflicted emotions. Not even Aunt, his one, unlikely friend on the ship, could understand his resistance to the idea of becoming "Whole." He knew he must, if he could; every day he spent in his human body he was gambling with his life.

<Not that you'll ever know,> he replied instead. <I doubt they'll waste any precious communications time to report on me.>

<It is your life,> she said simply. <It does not matter what I know.>

He looked down at her solemnly. Her immobile face belied the unique and compassionate being inside. He spontaneously sent a burst of prickly gratitude towards her, then swiftly looked away.


	6. Chapter 6

He'd been sitting still for awhile now. At least, he believed so. He'd felt no movement and the only sound was a constant low machine hum. He could hear nothing else--not a hint of another person. Not even Sherlock.

He could probably work the zipper free on his own, but he didn't relish the idea of popping out of a suitcase alone in the middle of an alien ship with no intel and, quite possibly, no backup. Even if he was invisible. So instead he sat, curled in on himself, and continued to wait.

It bought him more time to figure out what on earth he was going to do next, at any rate. Denied the relaxation of John's earlier attempt at dozing, his muscles were beginning to bind and seize. His right foot had gone numb some time ago. The visions and voices from what he assumed had been Sherlock's memories replayed over and over in his mind. The tension in each remembered scream knitted knots along his spine. He worked hard to stay calm, focusing on breathing evenly through his nose. Musty canvas and fresh laundry mingled scents each time he inhaled, and the air felt hot and close. He rubbed his jaw gently against the soft shirt under his cheek in an attempt to ground himself. John blinked his eyes in the darkness, suddenly understanding what it meant to truly feel _trapped_.

John trusted Sherlock. He had to. He couldn't trust Sherlock not to lie, or to consider John in any way, or to do anything for reasons beyond his own self-interest. Rather, John trusted Sherlock to be himself: a vibrant flame that could warm him or scorch him by turns. The trick, John had found, was to watch where the wind was blowing, and learn to stand so he could see where the flame cast its light.

He'd decided long ago to risk the burns for the ability to stand with Sherlock as he pierced through the darkness around them. John had made it his duty to guard the flame from those who would try to put it out. But he wondered now, for the first time, just what exactly was burning to make its light so bright.

The sound of a zipper broke through John's thoughts. John felt a pressure just behind his eyes. He inhaled deeply once more. 

"Jesus Christ," he whispered as he exhaled with a gust of breath.

He felt a coolness on one side as the lid of the suitcase was flipped back. Without waiting for an invitation, he shrugged off folded clothes and struggled to get upright. The wild movement of his elbow collided with a _thunk_ against his liberator's chin.

"Ouch," Sherlock hissed. "John, stop moving! You should have stayed still until you knew it was me," he chided, rubbing his jaw and frowning.

"Of course it was you, you great bloody git," John spat. "I felt... nevermind. Just let me get up."

He continued trying to organize his limbs. How had he known? He'd _felt_. That pressure, the one behind his eyes. Somehow, he'd known that had meant Sherlock was nearby.

Sherlock had backed up, going from a kneeling position to a wary crouch after taking the blow to his chin. He looked every inch the same as when John had last seen him some hours before. He was holding a two black, plastic objects under his arm.

The room John saw around them was rather small and unremarkable. A series of empty shelves and drawers lined the longer wall to John's right, and the floor to his left contained a recessed, cushioned pod. Otherwise, the area was gray and bare and dull in the dim light.

"Where are we?" John asked, finishing the cursory examination of his surroundings. 

"My quarters," Sherlock replied simply. 

"You have a room here, on the ship?"

"Of course. Though I haven't been here in ages," Sherlock said offhandedly. "It's rather difficult to see clients inside a spaceship hidden at the bottom of the Bristol Channel."

John couldn't help it: he laughed. It was just a short titter--nearly a chortle--but as it burst out he felt some of the knots in his spine clear out along with it. "So I imagine they think you're moving back in, is that it? That you've brought this suitcase over because you've gotten bored with detective work?"

"Something like that," Sherlock agreed easily. "Now stop wasting time, we've got to get going."

"No," John said slowly. He rotated his foot and massaged his insole, trying to restore feeling to his toes. "Sherlock, there's something I need to know first," he began.

"Not now," Sherlock interrupted. "There will be others here any minute. I have some duties to attend to before we'll be left alone to work. You've got to get up before they arrive." He gestured emphatically in John's general direction.

But he didn't move forward to help, and he didn't meet John's eyes. Then John remembered: _invisible_. It felt strange to converse with Sherlock and not be scrutinized by his endless stare.

"Right." John bobbed his head and scrambled out of the suitcase just as a muted chime sounded at the door behind him.

Sherlock stood and thrust one of the objects he'd been carrying in John's general direction. "Put this on," he directed. "Stay close. Keep physical contact when you can."

The object clattered to the floor and John scrambled to retrieve it. It resembled nothing so much as a gas mask. John opened his mouth to ask for an explanation, but snapped it shut again upon seeing Sherlock don his own mask. John fumbled with the straps but managed to slip his on just as Sherlock whisked the door back and stepped briskly out into the light.

\---

John strode forward to keep up and nearly stumbled as he crossed the threshold into something different.

One step had propelled him through an invisible barrier just at the door. He noticed it as a coolness, and an increased drag on the motion of his legs. He raised his hands in front of him and turned his head from side to side, trying to see what he'd caught himself in.

His arms, too, felt the drag. Curiously, though, when he stopped moving them, they felt supported in place. He became aware of a gentle pressure across the whole of his body. It enveloped him like a second skin.

He turned again and caught a glimpse through the door he'd just exited. The view through the portal was distorted. No--it was refracted! He realized he was encased in some other medium: something thick and buoyant and not air or another gas at all. Yet it was no liquid, either, as he didn't feel wet.

Turning back again, John saw with a start that Sherlock was now many feet away, trailing behind some unknown human man. And neither man was walking. Rather, they were suspended in the middle of the tubular corridor, swimming forward at a lazy pace.

John kicked his feet to catch up. He slid easily into a crawl stroke, beating his legs to motor ahead.

He was breathing hard inside his mask, lightly fogging the view with each exhale. His face was warmed by his own humid air, yet each inhale came easily, and the fog in his mask dissipated. It really was a gas mask, then; it facilitated a gas exchange with whatever it was he was swimming in now.

As he caught up to Sherlock, who was moving forward with an unhurried breast stroke, new details sprang into view. The hem of Sherlock's jacket and the laces of his shoes did not hang down in deference to gravity. His curls fanned out around his head. They kept their shape but rippled with resistance each time Sherlock kicked. John looked beyond him and saw the corridor stretched ahead and appeared murky and blue in the distance.

John slowed his stroke as he approached. While he still couldn't be seen, he had no way of knowing whether their unknown companion might feel a wave from John's transferred motion. The other man was stretched out away from John, and John couldn't see much beyond his slipper-clad feet. The attached legs were encased in a jumpsuit of padded, dark red nylon. A dark-haired head bobbed in and out of view.

It was at this moment John realized that the medium surround him was also pressing in its silence. He could feel his own breath against the back of his throat, but his ears outside the mask did not perceive it. The stranger's nylon clothing created no telltale crackle or rustle. No other sound penetrated the envelope around.

A flash of motion to his left startled him out of his crawl. He turned to face the movement and was astonished to see another creature like the one that had appeared in the Baker Street alleyway a few short weeks ago. But this creature--this Host, this alien, two-in-one--did not resemble a snake so much as a torpedo. Straight as an arrow, it rocketed down the corridor without even a passing glance their way. What John had taken to be wide silky hairs covering its body were behaving like cillia, beating madly in rapid peristalsis and propelling the being on. Its tentacle-like appendages hung like flowing streamers rippling in its wake. As suddenly as it had come, the strange being was gone.

And John began to laugh. _Not_ just a blue snake alien with jelly brains, then, but also a hyperintelligent paramecium! Engaged in intergalactic diplomacy, or perhaps human torture and enslavement. Hard to say, really, at the moment. He'd have to ask Sherlock when he got a chance.

_Sod this,_ John thought, and he turned a sloppy somersault in the middle of the corridor just because he could.

\---

Their journey ended in a dim, cramped room that reminded John strongly of a repurposed supply closet. Everyone's masks were off and their feet firmly on the ground: this room was back to regular air. It smelled stale. John ran a hand through his perfectly dry hair and stifled the urge to cough and sigh.

Sherlock had boosted himself up onto a very ordinary-looking exam table. John scanned the room quickly for a place to hide out of the way of their unknown companion. He spotted some familiar medical equipment--an automatic hematology analyzer--and scooted to get behind it. On the way, remembering Sherlock's directive, he swiped at his friend's elbow to alert him to his location. Sherlock twitched, and though John thought he probably imagined it, it seemed as though the set of Sherlock's shoulders began to relax.

Those same shoulders tensed up again as the third man approached Sherlock carrying a blood draw kit.

"Good to see you again, Sherlock," the man said cordially. His soft, dynamic voice harmonized with the appearance of his bright smile and shining chestnut eyes.

"As ever, Sudeep," Sherlock sighed. He thudded one foot against the exam table in a restrained show of petulance.

"How have your symptoms been lately? Any more storming, since last we spoke?" Sudeep had set the kit down and was sanitizing his hands, preparing to lay out the necessary materials.

_Storming?_ John thought, feeling a prick of concern. That term usually applied to a serious side effect of major brain damage--and not a subtle one, at that. But he'd never seen any evidence of Sherlock experiencing sympathetic storming. Perplexed, he evaluated the other man's technique as he swabbed Sherlock's arm with an alcohol wipe and prepared to place a rubber band around his bicep. _Christ, what am I thinking!_ John rubbed his forehead to dispel the pressure gathering between his eyes.

"Not at all," Sherlock replied. "I've been fine. Everything in top shape." His tone was clipped and cool.

"Liar," Sudeep retorted with another grin. "You're testing me again. You know I can always tell." 

"Then why ask," Sherlock grumbled under his breath.

Sudeep donned a pair of nitrile gloves and picked up a butterfly syringe and collection vial.

When he flipped off the protective needle cap, John felt a surge of fear jolt through his heart. He slapped his hand across his mouth to keep from crying out, praying that the small smacking noise wouldn't give his position away. Pupils blown wide, he raced to assess the situation and figure out how to gain control.

_STOP!_ one corner of his mind shouted as the rest of his brain ran ahead. Where was the threat? There was no threat. It was a sanitary needle, a simple blood draw. _Stand down!_

Then Sudeep grasped Sherlock's arm, extending his elbow. A second flush of panic raced through John's chest. Sudeep moved the needle into position and Sherlock looked away. 

The panic John felt was acid green. John realized suddenly that he was observing two scenes: one here in this room, and another inside his mind. Or more accurately, Sherlock's mind--the panic was Sherlock's voice, his real color-voice. Observing more critically now, John could visually see Sherlock's fearful emotions in his stiff posture and tightly-shut eyes.

Sherlock was afraid of needles?

Sudeep expertly pierced a vein and began to collect a blood sample. Crimson spurts of liquid slowly filled the tube.

Wait, forget the needles. Sherlock was _still inside his head?_

John mentally hurled a string of invective that began with "you absolute bloody wanker" and went downhill from there. His tirade lasted for the length of the blood collection--four vials' worth--but in all that time he got no response. Sherlock's physical expression did not even flicker, and John felt no shadow or hue cross his mind. Was it a one-way only connection, then?

Breathing. Yes. He had to be steady, and quiet, and remain in control. While he watched, Sudeep finished the draw and stopped the bleeding with a cotton ball and fabric tape. He tossed his gloves into the bin and gathered up the vials.

"All done!" he said cheerily, turning away and beginning to walk towards John. Sherlock grasped at his bandage and let his head loll back with a small sigh.

Sudeep headed for the hematology analyzer. Standing at the machine, he was very close to John. His hands disappeared below John's field of view, fiddling with the samples and the machine's controls. John remained very still and decided to take the opportunity to observe.

The man in front of him was only slightly taller than he was, though with more than a bit of a sedentary labworker's   
plump waist. The warmth of his honey brown skin seemed to be the physical embodiment of his sunny disposition. He was obviously some kind of medical professional, and apparently knew Sherlock quite well (and was astonishingly unfazed by him to boot).

Although now that the man was standing before him, John realized that something was off. Sudeep's formerly mobile, expressive features had settled into stone. He did not display the furrowed brow of a concentrating worker; rather, his face and eyes had become entirely blank. Though his hands appeared to manipulate the machine with skillful efficiency, his gaze was directed elsewhere, at some midway point in space.

John knew that look. He knew it very, very well. It was identical to the expression Sherlock wore when he was roaming around his mind palace. This troubled John, though he couldn't say why. Actual humans did use the mind palace as a memory technique, and Sherlock had to have gotten the idea from somewhere. But the look on this man's face was simply uncanny.

A few moments later, a switch was flipped and Sudeep's dark eyes lit up again. His reanimated features molded themselves into a pleasant smile before he turned to face Sherlock once more.

"Alright, you're free to go," he announced. "I'll have to do a more thorough exam before you leave, of course, but this will do for now."

Sherlock leapt off the exam table and straightened his shirt. He began to move towards the door, then checked himself. He stopped and swept one arm in a grand gesture. "After you," he insisted.

Sudeep chuckled. "If you insist," he agreed.

He walked out of the room, and John took the opportunity of Sherlock's well-timed delay to hurry out after.


	7. Chapter 7

In a deserted part of the corridor, Sherlock stopped short and threw his hands out wide. He kicked his legs to orient himself upright, then craned his neck around. John realized he was searching for him.

Feeling contrary, John did not oblige immediately. Sherlock spun about and John could see his lips moving inside the mask's face shield. He waved his hands about methodically, as though searching for something in the dark. John was mollified by his little rebellion after another moment; he moved forward and caught one questioning limb.

Sherlock immediately turned the tables and grasped John's wrist like a vise. He brought his other arm around and found John's opposite shoulder, tilting his head to look dead on into the space in front of John's eyes. John shivered a bit under Sherlock's exact and penetrating stare. Its message was clear: don't do that again.

Mutely, invisibly, John nodded.

Perhaps Sherlock had felt his movement, or perhaps he simply anticipated John's capitulation. Either way, he dropped his stare and pivoted, transferring John's captured arm from his own hand to his right shoulder blade. He pressed down once. _Stay._

John adjusted his grip and allowed Sherlock to pull him along as they kicked off into an economical swim.

Less than a minute later, John saw that the corridor was about to come to an end. It appeared to open up into a larger, somewhat murky space beyond. A few more strong kicks brought them over the threshold.

John looked down. His heart leapt into his throat and he instinctively grabbed hard at Sherlock's shoulder.

They'd entered the top of a chamber, and the very bottom was at least eighty feet below. Vertigo overrode the feeling of support from the medium surrounding them, and John had to stop kicking and focus instead on continuing to breathe. Sherlock glided on, unperturbed by John's sudden shock. He pulled him along with ease.

The large chamber was evidently some sort of gathering place. A dozen corridors on five levels connected to this space, creating regular, round openings in one of the chamber's curved walls. The other walls together created a clear bubble window out into the cloudy water beyond. The outer world, illuminated only by weak, filtered sunlight, appeared barren save for a school of tiny fish visible just below John's eye height.

The fish outside warranted only a passing glance, however, in comparison to the environment inside.

The Host thronged within the chamber. Some were in transit, following invisible currents like spiraling corridors up and down from level to level. Others congregated in pods outside the main flow, tangling bodies and appendages into knots that seemed, to John, shockingly intimate for a public space. The eerie silence within the gel made the scene even more unreal; the wriggling, flashing blue bodies could almost be a vision, or a dream.

Sherlock steered them towards one of the curving downward currents, and they were immediately sucked in. John grabbed at Sherlock with both hands now. As they rocketed on, they joined more and more Host merged with the stream. The other bodies pressed close, but, miraculously, John never felt a bump. He saw another human form pass them in the major current headed the opposite way, jarringly awkward and out-of-place.

Suddenly, Sherlock rolled to the side. John redoubled his grip but still his legs flung wide as Sherlock pulled them out of the flow. They were now at the bottom of the chamber.

John looked up at the swirl above. Whatever else might be happening, he couldn't escape a feeling of profound awe.

\---

The bottom of the chamber had led to a corridor that opened into another air-filled room.

"Do I have to keep this on?"

"While we're in the human-adapted parts of the ship, certainly."

"The human parts?"

Sherlock rolled his eyes. "As ever, John... did you not notice how the Host avoided you? They have sight but rely more on currents and vibrations in the gel to 'see' their surroundings. You've been perfectly visible to them."

His flippant tone vaporized the remnants of John's patience. 

"All right, Sherlock. Stop. Just stop it." He fumbled at the metal disc against his chest and yanked it off over his head. Sherlock's eyes snapped to his partly visible body. "If they can hear me they might as well see me," John said shortly. "Take this back."

When Sherlock made no move towards him, John threw the device down at his feet. It tinkled against the tiles.

"We're not here to investigate Dr. Miller's murder, are we," John stated. He stared evenly at the top of his friend's curly head; Sherlock was looking down at the now-visible disc on the floor.

"Well," Sherlock said after a moment, "I imagined we'd get around to it after a bit, but that wasn't my primary goal, no," he conceded.

John let out a nasal sigh. He clenched his fists, focusing on the bite of his nails into his palms. 

"And the primary goal would be..." he prompted.

"Well, um. Well. Showing you this. All of this, here." Sherlock gestured feebly with one hand. He met John's eyes only briefly before looking away.

All right then. Pulling teeth it was.

"Is it because you're sick?" John asked.

"In a way."

"Jesus, Sherlock, just--"

"I don't have a disease," Sherlock snapped, cutting John off. He puffed up and set his chin in his high-handed way. "There is a chemical incompatibility between my host and me. It's a chronic, unpredictable issue. I rarely have acute symptoms."

"Then what about the storming that technician asked you about? What's that then? Why haven't I noticed it? Hyperactivity of the sympathetic nervous system is not exactly a subtle experience!"

"You haven't noticed because I've taken great care to hide it from you!"

"Have you, then!"

"Yes, because I'd rather Mycroft not have to scramble your brains for national security!"

"Well... ta for that!"

The mounting tension reached a wobbly precipice. John remained taut and still; he had no idea what he wanted to shout about next, but he desperately wanted to leap over that edge. The ever-present mechanical hum of the ship felt leaden and large in the space hanging between him and Sherlock.

Sherlock took a step forward. "Don't you see, John?" His posture deflated slightly. "I'm showing you now. This is how I'm telling you. The memory erasure device only works within a short timeframe. If you've seen enough, for long enough, it won't work on you anymore. You'll have to be brought on board."

"Literally...?"

"No, no! I mean they won't have any choice but to allow you to know. To know about me, that is."

A swooping, soaring sensation flew through John's chest along with those words. It tickled like feathers. It was iridescent blue. Just then, John realized his own anger up to that point had been mixing with a fear colored acid green.

"I think I know a bit more than you realize," John said slowly. "Since you went inside my head, I mean. I think I'm still connected, somehow. I can... I think I can feel what you're feeling, when it's strong." The feathery sensation was instantly replaced by an absence in white. John rubbed his chest involuntarily. "I saw some things, too," he continued. His voice was calm now, and steady. "When we were traveling and I was in the case. I saw images of a woman, a frightened woman. She was screaming, and so were you. That's what I wanted to ask you about, back in your quarters."

After one beat had gone by, and then another, John cleared his throat and readjusted his posture. Sherlock was a statue. His eyes had glazed over. The blank whiteness remained. 

"Are you all right?" John asked after another moment. That, he thought to himself, was the question he really should have started with in the first place.

Too late, John heard the _snick, snick_ of nylon on nylon as a woman rounded the corner and saw the two of them in full-on view. Her soft, "Oh," made Sherlock twitch.

"Hello. Have we met?" she ventured. Plump and petite, she reminded John of a primary school teacher he'd once had. She began to juggle the large stack of papers she was carrying. Her fine, raven-colored hair fell into her face. "I know Sherlock, of course--looks like he's a bit lost in thought, hello--but I don't believe I've seen you before?" After wrangling the papers, she pushed her hair back and offered her free hand to John.

John stepped forward and reached out to take it. "Er--" 

"This is Eric. He's my new minder," Sherlock interrupted, reanimated. He pushed himself into the space between John and the woman.

"Oh, lovely!" She smiled. "I'm Melissa. Materials science. I've been in my own little world down here, didn't realize we had someone new. That must have been you shouting, then. Sherlock can be rather obstinate!"

John managed a half-hearted grin. "Right, well, we were just talking about going back to our quarters before, ah, his exams. Lovely meeting you." He looked meaningfully in Sherlock's direction.

"I won't keep you, then!" she replied. Sherlock had already begun striding down the corridor and John moved quickly to keep up. "Goodbye!" she called after them.

As soon as they'd left her behind, Sherlock thrust the metal transponder disc back into John's hands. John hadn't even seen him pick it up. He put it on without a word. A moment later, Sherlock stopped dead and put one hand out to his side, palm up. An invitation? A request? John hesitated.

"Your hand," Sherlock whispered.

Puzzled, John reached out and took his hand.

<Can you hear me?> Sherlock's voice resonated inside his head. John squeezed his fingers in response.

<One-way only, then. Convenient. Melissa is going to look you up, probably sometime in the next hour. When she can't find you, she's going to dither and debate for a quarter of an hour before calling her boss to let him know. Once that happens, we'll be cornered in minutes. We cannot escape the ship in that time frame. Our only chance is to go to Little Sister, now, and plead our case. You must keep up. Quickly!>

Sherlock dropped his hand and began moving apace once again.

\---

Little Sister's room was dim, hot, and apparently empty. John and Sherlock had floated up a vertical passageway in order to access this space, which was shaped like a calyx atop a stem. Sherlock twisted himself around until he lay suspended with his belly up towards the ceiling. Perplexed, John moved to follow suit.

As he rolled into place, John felt the gel surrounding him come alive. It was no longer a static support. Now it pressed, then released, in a mixture of massaging waves and prodding sticks. Unnerved, John squeezed his eyes shut and clenched his hands to force himself to remain still. He willed his plastic face mask to maintain its seal.

After a moment, he felt a different kind of bump, and then a hand grasping at his left elbow. Sherlock.

<She's inspecting you,> he explained. <Little Sister is the living being integrated into this ship; the gel medium is her eyes and ears. Arms, too. Just relax.>

John opened his eyes. Was it a trick of the low light in the undulating gel, or was the ceiling actually roiling? The grey surface flashed a deep blue color that then slowly melted back into a neutral tone. The gel stopped squeezing, and John felt cradled once again. A pulse of warmth bloomed in his chest and his head. Then he felt another, playful, flighty. John smiled.

<She's greeting us,> Sherlock said, interrupting John's flow of feel and thought. <Just... stay there, while we talk.>

_Hello, Little Sister,_ John thought to himself. _I already like you much better than Big Brother._ The warm feeling settled deep into his gut.

Though Sherlock kept hold of John's elbow, he was shrouding his conversation behind a mental veil. John caught only the occasional murky color. So while he waited, John simply watched. Sherlock's familiar face shone behind his own plastic mask. His lips curled into a dainty sneer, then unfolded into an exasperated gape before flashing through a small pensive smile. Then that smile was gone, and an eyeroll led into a conspiratorial grin. He was, in short, himself: John's mad flatmate, his Sherlock Holmes.

<Alright,> Sherlock said, at length. <She's agreed to help us. She and I... well. She is pleased to meet you and will keep you safe. You'll be her new game for the moment. She does love her secrets.> He sounded fond.

A ship with secrets? And these walls can talk! John suppressed a laugh. "What secrets?" he said aloud, then shook his head as the sound vibrated up his jawbone and died against his face mask. He turned then and grabbed Sherlock's hand. He uncurled Sherlock's fingers, then used his own free hand to trace letters against his bony palm. O-T-H-E-R S-E-C-R-E-T-S ? he asked, curious.

Sherlock blinked. <John,> he said. <Oh!>

Sherlock turned his hand around to grasp John's like a vise. He appeared to be speaking with Little Sister once again, but now let the content and images spill over to John. Amongst a riot of flickering color, John could make out snapshots of Dr. Miller's kitchen and Dr. Lacks, his wife. Other places and human faces he didn't recognize zipped by as well.

Lost, John grasped Sherlock's hand again, spelling out S-L-O--

<Miller's killer,> Sherlock backtracked to fill him in. <He was confident he wouldn't be discovered through internal investigation. He wanted Miller's wife to follow standard protocol and report only to her superiors. Why would be be so certain his secret was safe? Only because he'd entrusted it to the only person who could _literally_ make things disappear: he's somehow made this part of Little Sister's games, > he explained. <She loves puzzles, and secrets, and adores it when someone is able to surprise her. A difficult thing to do when she is integrated into every inch of the ship.

<I've asked if she'll let us in to play along,> he continued. <We may be able to sniff out what he's hiding, and with luck, we'll find him as well.>

Just then, a clear image of a door marked with geometric blue slashes popped into John's mind. Sherlock's <Ah!> of recognition followed: this must be Little Sister's answer, John realized. Sherlock rolled and dove for the exit, while John floated a mental _thanks_ to Little Sister as he hurried to follow behind.


	8. Chapter 8

The door (small, grey, and nondescript, save for those geometric blue markings) was much the same as the doors to its left and right. It was located, coincidentally, quite near to Sherlock's room. John surmised that the markings must be a numbering system of some kind, as they varied with the corridor's progression. The door was so intensely ordinary he and Sherlock overshot it at first and only realized the mistake about five doors later.

"Of course," Sherlock breathed as he stepped across the threshold. He snapped his face mask off and ruffled at his hair. "Little Sister can't see into areas without the gel. And _we_ couldn't see the door at first because she'd made it so... unimportant."

John ducked around Sherlock when it was apparent he wasn't about to move aside. The room was dark and cool, lit only by a source by the entryway. As his transponder was still in place, John purposely clomped on the tile to alert Sherlock to his location without having to verbally respond. Their recent encounter with Melissa the Materials Scientist had made him wary of unexpected people round the corner. 

"Oh, for god's sakes, John," Sherlock huffed. " _Neither_ of us is supposed to be here, so it hardly matters if you're seen now. You may as well take the transponder off."

"And I may as well leave it on," John responded in a low tone. "What are we looking for now, Sherlock? What do you see?"

The flip of a switch revealed a space about as large as the first floor of 221 Baker Street, with a workbench running up one side and shelving units protruding from the other. The workspace was neat and spare, featuring dozens of disappointingly familiar-looking tools hanging on an ordinary pegboard above the bench. One or two items stood out as somewhat unusual to John, but then again, he was no kind of mechanic. The distinctive scent of machine grease hung in the air.

Sherlock strode over to the shelving units. The rustle of his clothing made John wince in the otherwise silent space. He couldn't even hear the ship's hum in here, he realized. The room was soundproofed as well as physically hidden.

Sherlock hefted a metallic cylinder from the top of the nearest shelf. He turned it this way and that. Its surface was covered in corkscrew grooves that were marred by some light scratches, and upon close examination it revealed two joints around its middle.

"I recognize this," he said after a moment. "It looks like the object for a game the young ones took up several years ago. But this one... it's not as polished as the others I've seen. Not as flashy. You see, John," he turned, "it twirls through the gel and moves off in unexpected directions. I understand it is meant to be chased."

"Are those other things for games as well?" John asked, indicating the other items lying on the shelf.

"Yes. No. I don't recognize all of them," Sherlock replied. "The real question, though, is why a human is apparently playing games with Little Sister."

"How--"

"The workspace. Obvious. It's so familiar to you, you can't realize how very out of place it is. Even if the Host needed to use human-designed tools for some unfathomable reason, he wouldn't work in a setup like this." He dropped the cylinder neatly back into place, then ran his finger across the top of the metal. "Recently cleaned means recently used, or at least recently attended."

"Wait, you thought the murderer could have been one of the... the Host, before?" The few fully alien beings John had encountered had seemed the pinnacle of disinterest; John had never imagined that one of them would have gotten worked up enough to steal into a human home and plan a convoluted homicide.

"Mustn't theorize in advance of the facts," Sherlock grunted. "But if he only had access to hand tools then how...?" And he was drawn up inside his mind. The frown moulding his lips spoke of disappointment, rather than deep and concentrated thought.

A small _slop-pop_ sound caused both men to whirl around. There in the entryway, removing his face mask, stood Sudeep.

"Little Sister told me I had a new playmate," he said, smiling. "There was more to her story, but I'm afraid I didn't understand it. You think my toy shop has something to do with a scientist working topside?"

" _Your_ toy shop? Your _toy_ shop?" Sherlock very nearly sputtered.

"Mmm, my secret," Sudeep confirmed. He held up his hands and gave a sheepish shrug. "You've found me out. I've been working in here for years--you really are as good as they say, aren't you?"

John was never so glad to have disobeyed Sherlock's directions as he was right now. He stayed frozen in place, keeping his breathing shallow and steady so he wouldn't give his presence away. He stood barely two strides from Sudeep. If Little Sister had called Sudeep here, John wondered, had she mentioned anything about John to him too?

"Explain," Sherlock snapped. He drew himself into a regal, upright posture.

"It's my hobby," Sudeep went on. "There are so few of us humans who live on the ship full-time. We're always in one another's pockets. I'm sure you understand the need for a space of one's own?" Here, Sherlock made a noise of assent. "I made a deal with Little Sister many years ago. She keeps this room hidden, and I make her new things. We have fun," he finished with another small shrug. "You won't be offended if I ask you to keep this to yourself?" he asked.

John felt the hairs on the back of his neck stand up. Sudeep was shamming, he was sure of it--he had the same air of controlled verisimilitude Sherlock projected when he was playing a role. (John had gotten tired of being duped. He'd learned the trick was to watch for Sherlock to display flashes of intense focus in situations that should require almost none.) This man's actions were the very picture of non-threatening, and that put John on high alert.

"You're a biomedical researcher. When did you learn to create things like this?" Here, Sherlock held up the metal cylinder he'd inspected earlier.

John didn't bother to listen to the response. Instead, he crept towards Sherlock until he could reach the back of his shoulder with an outstretched hand. He wrote swiftly with his index finger: F-A-K-E F-A-C-E. Sherlock never flinched. But his eyes immediately went blank, and then, after a moment, he interrupted Sudeep's story with a forceful, "Oh!"

"Oh?" Sudeep asked.

"How does it feel, Cousin, to have tended to the person who caused your downfall for so many, many years?" He wore a feline, tight-lipped grin. "What did you think when you learned they planned to toss me back through the door?"

Sherlock's questions were gibberish to John's ears, but they clearly hit home with Sudeep: his persona fell away, and in its place stood the man with the blank face John had glimpsed earlier from across a hematology analysis machine. "Well then," he said.

His hand flew towards the breast pocket of his jumpsuit, and the swift motion spurred John to act as surely as a fluttering cape calls a bull. John launched himself forward and took the other man down in a tackle. They landed hard, but Sudeep was hardly fazed by his mysterious invisible assailant: he writhed and struck out until he was able to land a lucky blow across John's face. John fell back, dazed, and Sudeep seized the opportunity to wriggle free.

Sherlock had hung back, not wanting to get in John's way, but was now too far behind to catch hold of Sudeep before he dove through the entryway into the corridor.

"Come on, John!" Sherlock shouted as he followed suit.

John rolled over and put his hands out, searching for his fallen face mask. As his fingers closed around it, he realized neither Sherlock nor Sudeep had been wearing theirs. He snapped his in place and staggered out the door.

Both quarry and pursuer were many lengths down the corridor by the time John emerged. Sudeep's strokes were jerky but powerful, propelling him choppily on towards the large central chamber. Behind him, Sherlock's sinuous motions were like a shark's closing in on his prey. John, at the rear, felt like more of a guppy; he'd never been a strong swimmer but knew he must follow to see this through.

Then Sherlock stopped, limp and crumpled, and crimson blossomed around his head.

John gave a shout that died in his face mask and surged forward in a panic. He hadn't seen any weapon. Sudeep hadn't stopped or turned round. A roaring filled John's ears.

He squinted at the red substance pouring from Sherlock's head. It wasn't diffusing as blood would do; rather, it was coalescing, and then moving! It was Sherlock himself, John realized, wriggling onward in the manner of a cuttlefish. Sherlock moved twice as fast as he had been in his human body and overtook the near-frantic Sudeep easily. 

That same body suspended in the corridor drew John's attention away. The man was drifting, rotating from residual momentum. His eyes were half-open and his jaw slack. To see that dear face so still made John's chest feel tight and desperate, though his mind knew Sherlock was divorced from it entirely. John saw the comatose man's ribs expand--reflexive breathing! Would that pull the gel into his lungs? Would he drown here on this ship?

He looked back up ahead, but Sherlock was nowhere to be seen. Sudeep, however, had stopped moving forward. John was now looking at his back. His limbs had gone rigid and his face was tilted up. Could Sherlock have... gone _inside_ the man? Was he there in his head?

John finally reached Sherlock's abandoned body. He grabbed roughly at the face, shutting the jaw and clamping the nose. But what now, what now?

Retreat. John couldn't follow where Sherlock had gone, but he could save his transport. He hooked his arm around the man's body, and in a flash of clarity, knew exactly what he needed to do. Kicking and pushing against the cool gel, struggling to maneuver towards the nearest human-adapted doorway, he closed his eyes and looked inside his mind. With the clearest voice he could muster, he called, over and over: <Little Sister! Please, help!>

Suddenly, John's ears felt very full, and his stomach clenched. A brilliant purple blazed across his field of vision. It was the last thing John remembered before everything went black.

**Notes for the Chapter:**

> Happy American Thanksgiving! I would be very thankful for a comment or two... is it easy to follow what's happening? Is my worldbuilding too convoluted? (I stripped out a ton of complicated backstory and I worry that what remains might not entirely make sense on the page.)
> 
> Lots of emotional reckoning from here on out to the end. Get ready!


	9. Chapter 9

The tiny muscles under John's left eye began to reflexively shudder and twitch. He resisted the urge to rub his face, just as he abstained from picking at the loose thread on his right cuff. The soft, light blue cloth was a cut above what John imagined standard prison wear to be, but he was under no illusions about being in detention.

He'd woken in a spare room the day before. He'd been alone, curled on a narrow, hard cot with a blanket draped over his body. A glass of water on a collapsible metal table were the only other furnishings. Fluorescent lights shone down from above. He'd known immediately he was no longer on the ship at the bottom of the Bristol Channel; the comforting background hum was gone.

Since waking, he'd been largely left to himself. There was no toilet in his room--cell?--but knocking on his door resulted in a tall, burly escort leading him silently down a featureless hallway to the nearest loo. Meals were handled in much the same way.

Now, however, he was seated in an empty room, waiting for an unknown someone to walk through the door. The room looked as though it might hold conferences at other times--depressions in the carpet spoke of absent table legs and chairs--but now, all that remained was John's chair, a table, and an empty seat on the other side. John couldn't see any cameras, but that didn't mean there weren't any. So he waited, still as stone, mentally preparing to meet his interrogator. Then the door opened.

"Good evening, Doctor Watson," a familiar bland, yet somehow grating voice broke into John's thoughts. Mycroft. Of course. Sherlock had said he led the human-alien liaison these days.

"Where's Sherlock?" John asked, turning to meet Mycroft's eye as he walked into the room. Mycroft, however, looked down at the floor.

"Alive. In hospital--no, no, he's fine. His human body is ill," Mycroft began. "Did you know that human lung tissue can actually draw oxygen directly from the gel medium on the ship? Carbon dioxide exchange is problematic, however, and then there's the issue of getting the gel out again--"

"So he did aspirate," John interrupted.

"And has a rather plummy pneumonia as a result," Mycroft confirmed. He pulled the empty chair out, scraping its legs across the rug, and took a seat in a rustle of expensive wool on wool. He placed a plain briefcase beside him on the floor. Then he finally looked up at John. John spoke first.

"Can I see him?"

"Tomorrow morning, if you'd like. You'll want the evening to prepare."

John frowned, breaking his mask. "For what?"

"There are two stories you should hear," Mycroft continued. "I'm sure you'd like to know what happened after you lost consciousness?" Here he raised his eyebrows and leaned forward slightly in his seat. He went on without waiting for a response. "Apparently, your little experiment with Sherlock to allow you use of the invisibility device had some... side-effects. You became able to receive weak signals from the Host's telepathic communications, and even send out some signals of your own. After you called out to Little Sister, she initiated a full mind-link in order to find out the source of your distress. Unfortunately, that was all a bit overwhelming for your physiology. On the bright side, your faint led Little Sister to panic, freeze the corridor, and call reinforcements. And now here we are." Mycroft leaned back once again, causing his chair to creak.

"And... that's the bright side how, exactly?" John's mask was back in place.

"Because it resulted in the discovery and detention of the most devious criminal Sherlock has dealt with in the past fifteen years," Mycroft said, lingering on the final three syllables.

"Sudeep wasn't... it wasn't Sudeep, was it. He had a--a _parasite_ in his head, too." John had been thinking about Sherlock's outburst before the chase for the past two days. This seemed the most likely conclusion.

Mycroft sighed. "In this case, yes, I'd say parasite is the most appropriate word. The 'parasite' was PX974, a symbiote who was thought to have died with its host after a tragic event some time ago."

"But Sherlock called it 'Cousin'...?"

"Their race has a complex relational naming system," Mycroft explained, waving one hand dismissively. "We use codes in our internal government correspondence. Much easier that way."

"Is he all right?"

Mycroft gave him a quizzical look. "Well, as I said, Sherlock--"

"Not Sherlock. Sudeep. I mean, the real Sudeep," John explained. "If that's his name."

"Ah. Well. I suppose he's doing remarkably well for a man who was held captive in his own mind for a decade and a half," Mycroft mused. "Not to mention the final trauma of Sherlock bursting in to try to wrest control from his captor. Very inelegant." He sniffed delicately.

" _My_ croft."

"Indeed. Sudeep is being cared for. He is lucid, but not inclined to be communicative at present. But John, there's... we've so much to cover I hardly know where to start." Mycroft paused and looked down. He placed his hands flat on the smooth metal table.

John remained still. _Stone_ , he reminded himself. Still as stone. And yet, he was intrigued by Mycroft's last statement, or rather, by the way he said it. His voice had been smaller that usual. Almost lost. John let his silence stretch on.

Another moment passed before Mycroft looked up once more. "PX974 was once an ordinary member of the Host--a symbiote with a proper host body. It--well, _he_ \--led a group of underground rebels in carrying out a horrific plan to ultimately overthrow the governing body on their race's home world. The details of that story are recorded in here." Now Mycroft leaned down to unlatch the briefcase at his side and slide out a thick, olive drab folder. He dropped the folder in front of John with a soft thud.

"It was this plan that injured Sherlock so that he became unable to join with a proper host, and led him to take the form with which you are familiar. The difficulty, of course, is that Sherlock is still... ill... as is his human host body. Honestly, we've no idea how much longer he's got before severe deterioration begins."

John's breath caught in his throat. "Do you mean--"

"No, he's... all right just now. His pneumonia is only a pneumonia. He may have years left. Decades, even. We just don't know. He could begin to slide any day."

Blinking rapidly, John leaned in and set his own hands on the table. The coolness against his palms helped reorient him. He hadn't realized how tightly he'd been clenching his fists. "What can be, I mean, is there anything to be done?" he asked.

"Up until two days ago, the plan had been to send him back to his home world for treatment upon completion of the traveling Gate. The Gate was on schedule to be activated the day after tomorrow." Mycroft paused. "That plan is on hold now, as we've since discovered that PX974 sabotaged the Gate mechanism. If it had been activated as scheduled, the whole thing would have gone up like a bomb."

"That workshop," John filled in. "Where he'd told Little Sister he was making her 'toys.' He built the bomb there. Jesus." He wiped one hand down his face. "And he killed Dr. Miller because he'd been close, somehow, to finding out. He knew Little Sister would unknowingly protect that secret."

"Indeed."

Both men let the pause linger.

"John," Mycroft went on, "there's something else you must know. Once the Gate is repaired, if Sherlock goes through, he'll likely never return to Earth again." He took a deep breath. "Gate activations are short, and very rare at this stage. They're phenomenally energy-intensive. After Sherlock's medical condition is dealt with, his transportation will be given the very lowest priority level. He's not critical for the mission here, you see."

"You said 'if'," John probed. "If he goes through."

"Until two days ago, he was under orders to do so. But we've learned... rather a lot since that time. Officially, now, the Host will allow Sherlock to make his own choice."

Mycroft rose suddenly, scraping his chair back. "I thought I'd let you give him that news in the morning," he said brightly. "After that, you'll be free to go." He reached down to pick up his briefcase, then leaned across the table and extended his right hand.

John grasped it and they shook, once, before Mycroft straightened, pulling his suit jacket down into place.

"You've been given clearance through the highest levels of this enterprise," Mycroft said, adjusting his cuffs. "I do suggest you read that dossier before you go to visit Sherlock tomorrow." And then he turned, and he was gone.

\---

Anatomy and Physiology; Social Structure; Communication/Language; Moral Behaviors...

Apparently there was more to this dossier than Mycroft had intimated. This wasn't just some incident report; this was comprehensive documentation on the government's studies (both overt and covert) of the visiting alien race. If John had been handed this a week ago, he would have pored over each detail. Now, though, his eyes barely skimmed the pages. What was the point of internalizing all this knowledge when the only alien who mattered to him at all would be leaving for good?

Because he had to go, didn't he? Mycroft had said Sherlock might still have decades in his present condition, but this document was telling him a normal lifespan for his race could be hundreds and hundreds of human years. Sherlock was still a child by that standard. (And wasn't that an odd thing to consider.)

John leaned back against the wall and closed his burning eyes. He was sitting on the cot in his faux cell, cross-legged with papers from the folder spread out around him. A long exhale parted his lips.

He thought back to the day he'd come home from the clinic to find Sherlock chatting up a "big, blue snake-thing" in that alleyway. He'd been so angry. Angry because he'd thought he'd been drugged, and then angry because Sherlock was keeping things from him. He _still_ felt angry, but now that was all knotted up with other emotions John couldn't even begin to name.

Leaning forward once more, John leafed aimlessly through the piles arrayed on his cot. He stopped when he found a packet labelled, helpfully, "Incident Report 05119." This was probably the story Mycroft had especially wanted him to read. He picked it up.

Twenty minutes later, he put it down and buried his head in his hands.

The rebels Mycroft mentioned hadn't been a simple militant group--they had kidnapped infant symbiotes and performed sick procedures to place the infants inside _human_ hosts. From what little John had gleaned of Host culture, this violation of the natural, two-in-one host-and-symbiote order was horrifically debased and vile... to say nothing, of course, of the human enslavement.

There was a photograph in the file that John recognized. It showed a human woman: the same woman he'd seen in the mirror in Sherlock's memory. Apparently, she (they?) had escaped their captors, and had wandered lost in some small town for hours before an ordinary Host worker, out on assignment, heard the young symbiote's psychic cries of distress. The Host's retribution against the rebels was swift and blunt, but they could not save the victims from their experiments. All but one of the little symbiotes sickened and died from their exposure to toxic human biochemistry. For this, the rebels had been executed--all save one, PX974, who was thought to have been killed in the initial pursuit. (Apparently, the two-in-one mentality was so ingrained that no one had thought to check whether the symbiote had died along with the body of its host.)

No one knew what to do with the lone little symbiote survivor. They tried to pair him with a true host, but the host had fallen ill and they removed him again. Something had happened to him, something that had protected him from the human toxicity but now made him dangerous to his own kind. The Host were frightened of him. To them, John thought, he must have seemed like a child missing a head. He was Half and could never be Whole.

Not long after, serendipity had given him the body of a teenage, comatose John Doe, and he became the boy who grew into the man John knew as Sherlock Holmes.

John could imagine the rest from there. Now he understood Mycroft's constant worry and obsessive surveillance. Sherlock did not belong in this world or any other; figuring out just what to _do_ with him must have been a moment-to-moment battle. Truthfully, he was shocked Sherlock was given so much freedom. 

Then he remembered what Sherlock was like when he was bored. His mouth twitched into a grin.

John sat back and surveyed the papers piled around him once more. Why exactly _had_ Mycroft given him all of this?

And what on Earth was he going to say to Sherlock when he saw him in the morning?

\---

Several floors away, Sherlock lay in a big white bed in a makeshift hospital room. He'd been left largely alone after the explosive conversation he'd had with Mycroft that morning. Now, he just wished he were tired enough to sleep.

His new doctor--some woman he'd done his best to ignore--had told him earlier he'd feel worse before he began to get better. She was damnably right: his body felt heavy, now, and he somehow lacked the energy to shift himself, through he could tell a crick was beginning to develop in his neck. He blinked languidly and continued to gaze without seeing at the off-white ceiling.

Purgatory. That's what this was. He was trapped in this horrible body, this sea of grey, awaiting passage to the next plane. Only, what awaited him on the other side was decidedly _not_ his idea of heaven.

His heart ached for home.

**Notes for the Chapter:**

> As I mentioned before I stripped a ton of worldbuilding and background from this story. (Mostly because I didn't want to do the ACD thing of putting a whole separate story into the main story because that's just rude.) If you're confused by anything I've written into this backstory, just ask! Want to know why child-alien Sherlock has no alien parents? Or why the rebel group was taking over human hosts? Or how they managed to hide the theft of symbiote infants? What the heck is a capital-H Host vs. a host? I've got answers for it all.
> 
> But, really, you just want to know what's going to happen when John sees Sherlock tomorrow morning. Right? And I totally dig that too. :)


	10. Chapter 10

"Dr. Kapoor?"

John stood in the doorway of Sudeep Kapoor's temporary quarters. When a man had come to retrieve him that morning, he'd impulsively asked to see Sudeep before visiting Sherlock. His escort had merely raised his eyebrows before leading him up to this room.

Sudeep's room was much like John's had been, with a few additions apparently meant to make it feel more "homey." Sudeep himself was actually sitting on a low-slung sofa beneath a framed print depicting a bland pastoral scene. The table in front him contained a few books and magazines, as well as a vase of cut flowers. The lilies had just opened; their sickly scent permeated the air. 

Sudeep didn't respond to John's summons. He was hunched forward and appeared lost somewhere inside himself.

"Er, I know you won't recognize me--I was a bit, um, invisible when I met you on the ship. But I was with Sherlock, before. I'm the one who... tackled you, or I suppose the _other_ you, in that workshop. I don't know if you remember? Um. Anyway, I'm John Watson," he rambled. He couldn't figure out what to do with his hands.

At this, Sudeep looked up. "You are... John. Doctor Watson?" he asked, slowly, after a moment had passed. His eyes were riveted to John's face.

"I am," John confirmed, returning the stare as evenly as he could manage. 

He waited for Sudeep to go on. Sudeep only continued to stare.

"Have you heard of me?" John finally prompted.

"Yes," came the reply. 

More silence.

"Um. Okay," John picked up. "Well, I wanted to... you know, I don't really know why I came, actually. Maybe to say I'm sorry, you know, for what's happened to you. And I don't have any idea what they're going to do with you now, but, I imagine you might--"

"Listen," Sudeep interrupted. John shut his mouth with a snap. "When I was here"--Sudeep pointed to his temple--"trapped, I decided, eventually, that I would pretend I was not trapped. I was only watching a film, a very long film. Do you understand? Sherlock was the star of this film. You see, I was the nearest thing to a medical doctor with clearance on the project, so I was assigned to monitor him and his body. Or rather, my Demon was. My Demon was the villain. He had to use Sherlock's blood to keep my body from rejecting him." He paused, blinking. "And so I watched Sherlock begin to grow up. And you're Dr. Watson." Once again, he fell silent.

"Right," John said, gravely, as though he understood.

Sudeep sighed. "I remember the day, over a year ago now, when Sherlock came to his regular appointment with me and my Demon. But this visit, it was remarkable. Remarkable! He spoke of you. His doctor. And, I think, his friend."

"Well, I... I should hope so," John offered in the space after this declaration.

Apparently, nothing more would be forthcoming. Sudeep eventually looked away.

"Dr. Kapoor, I... thank you for seeing me." John released a breath he hadn't realized he'd been holding. He swung his arms a bit, feeling out their tense springiness. "If there's anything I can do, please, um, just let me know." He nodded, punctuating the platitude, and turned to go.

"John," Sudeep called. John looked back. "I have a wife, Anna, and a son. David will be seventeen next Thursday. I have not seen them in... many years. And I do not think it is likely I will again."

The lump that surged into John's throat gave him pause before he could respond. "I understand," he said finally. He met Sudeep's dark gaze for one long moment before straightening up and walking out the door.

\---

Sherlock was awake. Skinny and pale under his greasy dark hair, he lay listlessly in his hospital bed. A peripheral IV line snaked into one forearm, and a clunky monitor was clipped to his index finger. The vitals display was silently flashing reassuring numbers in a lurid orange on black.

The quiet of the surrounding room exposed the shallow, wheezy rattle of Sherlock's breaths. He didn't look up at John as he entered, preferring to stare into middle space with half-lidded eyes instead.

"Mycroft left your mind intact, then," he spoke in a gravelly whisper. "Hurrah for that."

John paused where he stood, unable to place Sherlock's tone. He sounded defeated, and flat. But what did he think had bested him?

"He did me one better. I've got clearance now. I know the... I know your story."

" _Well_..." Sherlock responded. His sarcastic drawl was punctuated by a tiny, ineffective cough. He curled his lip in annoyance and tossed his head as though to shake invisible hair from his eyes.

That gesture, that little snarl, struck John like a lightening bolt. He finally, finally understood. He understood what Sherlock needed... and he knew what he had to do.

"I... I was eleven. My father died when I was eleven. I thought my world was ending," John began. He stuffed his hands into his trouser pockets and worried at their smooth seams. He thought he might be about to make a speech. He needed to stay standing.

"And in a way, it was. My dad was the world to me. I wanted to be just like him, learn everything he knew. He'd just started to teach me about rugby when he was diagnosed with an aggressive colon cancer. He was dead within three months. Right before he died, he told me I had to be strong for Harry and my mum. That it was my job to take care of my sister. And that... that's how it all started. My father's death and those orders are what started to turn me into _me_."

He twisted his mouth into a frown, dissatisfied with his clumsy language. "My dad was the kindest man I've ever known and I still miss him to this day."

The story was met with silence. John covered the lull with the rat-tat of a cough that also served to push down the lump forming at the base of his throat. He rocked back on his heels, just to feel his weight and the ground. Then:

"The world didn't end, of course," he continued. "I grew up. Mum died in a wreck when I was nineteen. That tipped Harry over the edge into alcoholism and sent me packing for the Army," he trailed off, taking a moment to recollect his thoughts.

Sherlock gave no response, save the increasingly laborious wheezing of his breaths. The ugly noise eventually broke through John's woolgathering.

"Cough," John commanded, putting his stories aside. "Come on, you've got to cough it up."

Sherlock paused, swallowing, and then the awful rattle resumed.

John walked up to the bedside. He placed a firm hand on his friend's back. "Sherlock," he said levelly, "you've got to bring it up. That's why the doctors want you in this body, so you can keep it awake enough to bring up all the muck. Pneumonia is no joke. If you don't cough, he'll die."

A moment passed. Then a pitiful, wet, toddler-sized hack began. Sherlock followed it with a deep, crackling inhale that turned into full-chested barks. John leaned over the bed, one hand still on Sherlock's back, the other holding a cheap white napkin to his lips to catch the phlegmy sputum he produced.

"Alright, good," John said after a moment, warm and low. "Don't make yourself sick. That's good."

John tossed the napkin into the bin as Sherlock quieted down. Sherlock still avoided his gaze and eventually shut his eyes entirely. John squeezed his shoulder and sat down in the hard plastic chair by the bedside.

"I don't have any war stories," John continued, unfazed. "I trained up over a few years, learned medicine, then I got sent out. I saw a lot of things. I dealt with a lot of things. But the thing is, a story is something that's got to have a point. Beginning, middle, end."--he demonstrated with his hands--"You know, punchlines. But nothing over there makes any damn sense. You're just in one middle until you find you've stumbled into another one, and when you leave it's like someone forgot to tell you how it all ends.

"I miss it. Missed it. Used to miss it more, I mean. It was easy to know what mattered: your life, and your mates' lives. And I was damn good at protecting both.

"You know the next bit, of course. Sent home, injured, no job, no purpose. I'd failed Harry and my family. And I was an old man then, wasn't I, at thirty-nine? I thought my life was over. Or if it wasn't, that maybe it should be." John sighed and kneaded a bit at the worn fabric on the knees of his jeans. He looked as though he might be about to grin.

"And then I met you. And now look at me." Now he did grin, knowing Sherlock would hear it in his voice. Then he steeled himself to drop his first bombshell.

"Mycroft asked me to come in here to say you're allowed to choose whether you want to stay." He said this firmly, knowing it would bring Sherlock to attention.

John was right. Sherlock twisted around like a cat, eyes wide and sharp as ever, searching John's face for any sign he was joking. Sherlock opened his mouth but John cut him off before he could speak.

"But I'm really here to tell you that you've got to go." John set his jaw and sat back in his chair.

"What?" Sherlock croaked. "Don't be ridiculous!" His splutter sent him into another round of gasping coughs. He waved away the new napkin John tried to push into his hands.

"Listen to me, Sherlock," John said over him. "All that stuff about my life? I've never... I've never told that to anyone before, at least not all of it. So I hope you were paying attention."

He leaned in and laid his hand on Sherlock's forearm. He felt, somehow, that there was a part of Sherlock that believed irrationally that touch couldn't lie. Sherlock didn't pull away. He watched John intently, radiating anger and confusion John could feel like white hot stars running up his arm.

"I wish my dad could have met you," John said after a moment. "If someone gave me the chance to go back and save him, somehow, I'd go in an instant. No questions." He began stroking his thumb over the soft hairs of Sherlock's arm. "But what I'm trying to say with these stories, what I meant... what I mean is--" He grunted, fumbling for words. This was why he didn't like speeches.

He found his voice, and continued. "You're scared. And... and it feels like this is it, that this is all there could ever be. But it isn't. You're supposed to live for a thousand years. I love you, Sherlock, and if you stay here to die I will never forgive you for it." 

The moment stretched on. Dark eyes held light ones, blue gazing into blue. 

When John tried to move away, Sherlock's face twisted into a glare. He shifted and brought his free hand up to John's temple. His IV line draped across his body and dangled in the space between them. He was close now. John could smell tangy sweat-scent of a broken fever and too long without a proper wash.

Images, memories, and thoughts began flashing through his mind's eye. An echo of the horror the first time Sherlock awoke in someone else's head. The feeling of invasion after he was rescued and introduced to a "proper" host. The sick terror of experiencing the host's physical and chemical rejection. Blissful silence in the young coma patient's brain, and the thrills of learning to pass as human. John observed Sherlock's increasing disconnect with the hyperopia of his own kind and the development of his obsession with the _now_ , with fleet thinking and stimulation. He was like a baby raised by wolves. He was Pinocchio. He'd become a real boy.

And then John saw himself. It began with that tangerine-rimmed image of John suppressing a smile. Then random jumbled memories of rooftop chases and quiet mornings blinked by, each suffused with a copper-red glow.

John's face felt hot and his eyes welled with tears. He raised his arm to cover Sherlock's hand with his own, pressing it firmly against the side of his face.

"Oh, my... you," he whispered. He turned his head and pressed against Sherlock's smooth, clammy palm, then gently lowered both their hands to his lap. He'd scooted right up next to the bed, and curled over the edge.

"What's my name?" John asked softly. "In your language, I mean. My relational name."

Sherlock did not hesitate. "Brother," he said, in a hushed, reverent tone. "Or, sometimes, I like to think... Water-Brother*."

John closed his eyes. There was pressure in his head, and light, and a haze of gold.

**Notes for the Chapter:**

> *Note: "Water-Brother," from _Stranger in a Strange Land_ (Heinlein, 1961), means "those who have 'shared water', that is, affirmed mutual complete trust, understanding, and acceptance." Other possible connections or connotations are left to the interpretation of the reader.


	11. Epilogue

"I've come to say goodbye."

Lestrade's head shot up and he cast about to find the cheeky bugger with the loud voice. He paid for a private care home for a _reason_ , damn it all. As he blinked blearily at his surroundings, he realized he'd fallen asleep--again. 

"Just resting my eyes," he muttered, then coughed. Finally, his gaze alighted on the fuzzy image of a figure standing in the doorway to his room. He pushed his glasses up his nose and the figure came into focus. "Sherlock?" he rasped.

"Obviously," Sherlock replied.

"You've come for what now?" Lestrade asked, peering up at him.

"I've come to say goodbye."

"Well hello to you, too!"

Lestrade shifted in his reclining chair with a sign. The man _had_ to be a bloody vampire, he thought, setting off on a wander down a well-worn mental path. He figured Sherlock had managed to flip some switch about two decades back, and the universe had obligingly preserved him in a stage of "mature" good looks. His black hair had distinctive sweeps of silver round his temples, and his keen eyes had lost none of their sharpness. Nothing was puffy, or gaunt, or sunken about his features. Meanwhile, he (Lestrade) had sailed right through his own silver fox phase until he'd reached elderly, and then old. Right now, he felt positively decrepit.

"What's this all about, then? I'm not dead yet," Lestrade quipped. Then he grimaced. "Er, sorry."

Sherlock's stoic gaze flicked away for a moment. "Indeed," he said at length.

"I'm sorry I couldn't make it to the funeral," Lestrade said to fill the gap. "I was in hospital, with--"

"With pneumonia, yes, I heard. I... apologize... for not sending a card."

At Sherlock's regrets, Lestrade's eyebrows did their best fuzzy caterpillar impression. "It's, er, quite all right," he stammered. Even after all this time he still couldn't parse the man. "But listen, I _am_ sorry, about John. Truly am."

"Thank you," Sherlock replied evenly.

"At least it was peaceful," Lestrade went on. "Passing in your sleep--that's a good death. Not many get that." He spoke knowingly; it was an all-too-familiar conversation, these days. And he couldn't resist the gallows humor: "Our careers wouldn't have been half so interesting if they did."

"Something I didn't appreciate for a very long time," Sherlock agreed. He remained rather subdued.

"John was a hell of a good bloke. One _hell_ of a good bloke," Lestrade stated, shifting to sit up further in his chair. "And he sure was good for you."

"John Watson was the greatest and kindest man I have ever known," Sherlock said forcefully. The sentiment seemed to burst out of him on its own accord, and then he moved at last, stepping forward and smoothing one trembling hand down his long coat. "And now I... well. He had some last requests. There's something I must go and do."

"And that's why you're saying goodbye?"

"It is," Sherlock affirmed. "So thank you, Greg, for everything."

He held out his hand, and Lestrade took it. He noted Sherlock was careful not to crush his frail fingers with his own sure grip.

"Ta," Lestrade replied. He would have said more but for the hard lump building in his throat.

With a solemn nod, Sherlock turned to go. 

Lestrade stopped him just before he reached the door. "Where are you off to, then?" he called out, not quite ready for Sherlock to disappear.

Sherlock turned his head back. The faintest of smiles curved across his lips, and his eyes crinkled at the corners.

"I am off to live for a thousand years," he said. And then he opened the door, and he was gone.

**Notes for the Chapter:**

> And that's all, folks. This story, imperfect as it is, represents over two years of work on my part. So if you've read it, and you could spare a moment to drop a comment, it would warm the cockles of my little heart.
> 
> Thanks again to my betas Niko and especially BiancaAparo, without whom this never would have been finished.


End file.
